A recent column by Gershon Baskin (January 22, “Prejudices and ignorance among Israeli settlers in the West Bank”) reminded me that “those who fail to learn from history are condemned to repeat it,” (Churchill paraphrasing Santayana).Our sages blamed the exile from the Holy Land on sin’at chinam – unwarranted hatred. Under siege by the Romans, Jewish factions blamed each other and fought to the death, doing the work of the Romans for them. Sadly, we are in a similar situation today. Our continuing failure to achieve peace with our Palestinian neighbors may very well be attributable to needless hatred between Jews. Palestinians have no incentive to agree to any peace plan when rejecting it causes Jews to become incapacitated, blaming and fighting each other. Divide-and-conquer is the easiest way to defeat an enemy. Furthermore, if we Jews can’t live in peace with each other, how can we be expected to do so with the Palestinians?Having understood the concept of sin’at chinam for millennia, why are we repeating our self-destructive history?The answer is simple: No one thinks their hatred is unwarranted. Rightist and leftist Jews are absolutely certain that the path of the other leads to mutual destruction. Thus, they experience each other as the enemy and feel fully justified in their mutual hatred. Neither realizes that the hatred itself is the true problem.The Home, founded by Inon Dan Kahati, is one of many grassroots peace groups fostering friendship between Jews and Palestinians. At “Cleaning the Hate” events, they get together to clear public areas of cigarette butts or other refuse. People who claim the Holy Land as their home cannot be treating it like an ashtray or garbage can.The Home also organizes lectures and panels, mostly at Beit Uri Tzvi in Jerusalem. Jewish leftists have been reluctant to speak at these events, so it was especially appreciated that someone of Dr. Baskin’s stature accepted the invitation to be a panelist at The Home’s recent symposium, “From Echo Chambers To Open Discussions – Not on the Same Page But Sharing the Same Stage.”It would have been nice for Baskin to thank The Home for the opportunity to present his views to a new audience. Instead, he wrote an article in the prestigious Jerusalem Post characterizing fellow panelists and audience members as prejudiced, ignorant and guilty of the modern sin of colonialism.Who among us can claim to be free of prejudice and ignorance? It’s human nature to see ourselves as objective and knowledgeable, and those who disagree as biased and ignorant. We humans have an uncanny ability to justify our own atrocious behavior while condemning the tiniest faults of others.HOW OBJECTIVE was Baskin? Did he not recognize that the other speakers – Kay Wilson, Rudy Rochman, Yishai Fleisher, to name a few – are all individuals of stature and accomplishment, and that they also know Palestinians personally and truly care about them?Baskin proudly recounted his role in constructing the deal that traded Gilad Shalit for 1,027 Palestinian prisoners, as though it was an unmitigated good. Yet he brushed off terror-survivor Kay Wilson’s concern that the release of masses of committed terrorists led to numerous subsequent murders of Jews.How about his accusation of others’ ignorance? Baskin wrote, “I have always tried to express that the Zionist movement was not a colonialist movement because it was based on the idea of people returning to their ancestral homeland. The modern-day Israeli settlers... are colonialists in their essence.”Is this a reflection of knowledge? Are Hebron, Bethlehem and Shechem any less a part of the Jewish ancestral homeland than Tel-Aviv, or even Jerusalem? Did the “occupation” following 1967 cause the deaths and displacements of nearly as many Arabs as the “justified” Zionist War of Independence?My intention here is not to criticize Gershon Baskin in particular or leftists in general, but to raise awareness of the pernicious moral epidemic of sin’at chinam infecting both Right and Left. In TV interviews, opposing politicians try to prevent each other from finishing their sentences as though their lives depended upon it. On social media and at political demonstrations, intelligent, educated people label each other fascists, Nazis, traitors and devils for no other reason than that they envision differing roads to peace.Sin’at chinam urgently needs to become a subject of public discourse or we risk destroying our nation from within. Left and Right must recognize they are not enemies. A healthy democracy needs both to flourish. Heaven help us if the entire nation were only right wing or left wing. One path could lead to a Third Reich, the other to a Soviet Union.Rav Menachem Fruman, zichrono livracha, an inspiration for many of today’s peace activists, instructed his audiences to clap their right and left hands together to symbolize the need for union of opposites. We should applaud the efforts of organizations like The Home to make that happen.Only when Right and Left have gotten rid of their gratuitous hatred will we have the strength and virtue necessary to achieve a real peace with our Arab neighbors.The writer has been a school psychologist and therapist for more than four decades. He is author of Bullies to Buddies: How to Turn Your Enemies into Friends, and writes a column for Psychology Today, “Resilience to Bullying.” He currently resides in Tekoa.