The Civil War happened because of slavery. To say otherwise is to lie. In the 1860 presidential election, Abraham Lincoln secured a majority of the electoral votes, and was elected to become the first Republican president. He opposed slavery and he opposed its expansion into the western territories. So before his inauguration on March 4, 1861, seven slave states with cotton-based economies formed the Confederacy. The first six to secede had the highest proportions of slaves in their populations, a total of 48.8% for the six. The Confederacy was created in order to preserve slavery; that was its primary reason for existence. While there are many explicitly racist quotes by Southern leaders at the beginning, during and after the Civil War that demonstrate the attitude of the Confederacy, the “Cornerstone Speech” by Confederate Vice President Alexander H. Stephens is about as clear as you can get for what the Confederacy was all about:
This new constitution, or form of government, constitutes the subject to which your attention will be partly invited. . . .
But not to be tedious in enumerating the numerous changes for the better, allow me to allude to one other -- though last, not least. The new constitution has put at rest, forever, all the agitating questions relating to our peculiar institution -- African slavery as it exists amongst us -- the proper status of the negro in our form of civilization. This was the immediate cause of the late rupture and present revolution. Jefferson in his forecast, had anticipated this, as the "rock upon which the old Union would split." He was right. What was conjecture with him, is now a realized fact. But whether he fully comprehended the great truth upon which that rock stood and stands, may be doubted. The prevailing ideas entertained by him and most of the leading statesmen at the time of the formation of the old constitution, were that the enslavement of the African was in violation of the laws of nature; that it was wrong in principle, socially, morally, and politically. It was an evil they knew not well how to deal with, but the general opinion of the men of that day was that, somehow or other in the order of Providence, the institution would be evanescent and pass away. This idea, though not incorporated in the constitution, was the prevailing idea at that time. The constitution, it is true, secured every essential guarantee to the institution while it should last, and hence no argument can be justly urged against the constitutional guarantees thus secured, because of the common sentiment of the day. Those ideas, however, were fundamentally wrong. They rested upon the assumption of the equality of races. This was an error. It was a sandy foundation, and the government built upon it fell when the "storm came and the wind blew."
Our new government is founded upon exactly the opposite idea; its foundations are laid, its corner-stone rests upon the great truth, that the negro is not equal to the white man; that slavery -- subordination to the superior race -- is his natural and normal condition. [Applause.] This, our new government, is the first, in the history of the world, based upon this great physical, philosophical, and moral truth. This truth has been slow in the process of its development, like all other truths in the various departments of science. It has been so even amongst us. Many who hear me, perhaps, can recollect well, that this truth was not generally admitted, even within their day. The errors of the past generation still clung to many as late as twenty years ago. Those at the North, who still cling to these errors, with a zeal above knowledge, we justly denominate fanatics. All fanaticism springs from an aberration of the mind -- from a defect in reasoning. It is a species of insanity. One of the most striking characteristics of insanity, in many instances, is forming correct conclusions from fancied or erroneous premises; so with the anti-slavery fanatics; their conclusions are right if their premises were. They assume that the negro is equal, and hence conclude that he is entitled to equal privileges and rights with the white man. If their premises were correct, their conclusions would be logical and just -- but their premise being wrong, their whole argument fails. I recollect once of having heard a gentleman from one of the northern States, of great power and ability, announce in the House of Representatives, with imposing effect, that we of the South would be compelled, ultimately, to yield upon this subject of slavery, that it was as impossible to war successfully against a principle in politics, as it was in physics or mechanics. That the principle would ultimately prevail. That we, in maintaining slavery as it exists with us, were warring against a principle, a principle founded in nature, the principle of the equality of men. The reply I made to him was, that upon his own grounds, we should, ultimately, succeed, and that he and his associates, in this crusade against our institutions, would ultimately fail. The truth announced, that it was as impossible to war successfully against a principle in politics as it was in physics and mechanics, I admitted; but told him that it was he, and those acting with him, who were warring against a principle. They were attempting to make things equal which the Creator had made unequal. (See http://www.ucs.louisiana.edu/~ras2777/amgov/stephens.html; Wikipedia provides a nice summary and discussion as well https://en.wikipedia.org/wiki/Cornerstone_Speech)
Whether you like it or not, the Confederate flag is inextricably tied to a racist sentiment.
In their study of Confederate symbols in the contemporary Southern United States, the Southern political scientists James Michael Martinez, William Donald Richardson, and Ron McNinch-Su write:
The battle flag was never adopted by the Confederate Congress, never flew over any state capitols during the Confederacy, and was never officially used by Confederate veterans' groups. The flag probably would have been relegated to Civil War museums if it had not been resurrected by the resurgent KKK and used by Southern Dixiecrats during the 1948 presidential election.
Southern historian Gordon Rhea further wrote in 2011 that:
It is no accident that Confederate symbols have been the mainstay of white supremacist organizations, from the Ku Klux Klan to the skinheads. They did not appropriate the Confederate battle flag simply because it was pretty. They picked it because it was the flag of a nation dedicated to their ideals: 'that the negro is not equal to the white man'. The Confederate flag, we are told, represents heritage, not hate. But why should we celebrate a heritage grounded in hate, a heritage whose self-avowed reason for existence was the exploitation and debasement of a sizeable segment of its population? (https://en.wikipedia.org/wiki/Flags_of_the_Confederate_States_of_America#Confederate_flag )
In the United States, if you want to fly the Confederate flag, that is your right, just as it is your right to fly a Nazi flag or the hammer and sickle, or to wear a Che Guevara t-shirt (Che was a murderous, totalitarian thug). You have the right to say anything you like, and to display any vile symbols you like, and believe and propagate any hateful racist propaganda you like. But I’ll criticize you for it, because I have freedom of speech as well. There is nothing good that can be said about the Confederacy or its flag, any more than you can speak well of the Third Reich and its flag. I see little difference between the two.
Will removing the Confederate flag from government buildings in the South and from the few southern state flags that bear it eliminate racism? Of course not. If you imagine banning a flag or any other hateful symbol will solve racism, you’re incredibly naïve. But if you want to argue that the Confederate flag is a good thing, then all you’re doing is self-identifying as a racist—or as ignorant—or maybe both. In either case, I appreciate the heads-up. As long as people continue to desire waving that flag, racism will exist. Banning the flag doesn’t change their desire or vile beliefs. Forcing people to outwardly conform does not alter their hearts or minds. As the Apostle Paul wrote regarding the imposition of rules and regulations, “Such regulations indeed have an appearance of wisdom, with their self-imposed worship, their false humility and their harsh treatment of the body, but they lack any value in restraining sensual indulgence.” (Colossians 2:23). Just because we make a law doesn’t necessarily mean we’ve solved anything.