There really is media bias?

I presume that you are aware of the mess at Rothertham which is in South Yorkshire north of London.  The sex-exploitation scandal.
I read this in an interview with Andrew Norfolk, who was the reporter who first broke the Muslim sex-grooming story

He admits that when he first heard details of the allegations by mainly white girls against largely British-Pakistani perpetrators – during a speech by Labour MP Ann Cryer – he didn’t want to follow it up. “Immediately I thought this is a dream story for the far right,” he says. Yet as soon as he started investigating in the autumn of 2010 he knew he would have to report on it: “We found clear evidence of a crime pattern that was not being acknowledged or addressed and which was having the most devastating impact on some of the most vulnerable, innocent people in our society.”

In other words, at another time, in another situation, it could have been possible that a reporter's own personal opinions and outlook could have swayed him to ignore the story because it would assist a certain other political viewpoint, despite the facts.
In this instance, Norfolk decided to act as per correct professional journalistic standards and, I presume, his moral moorings..
Another reporter at another time, however, could have followed his ideological persuasion and ignored the story and his obvious obligation to follow it up.  That would have been bias, one based on a particularly bad approach of prejudicial preferences.
And there is this, too:

Nor does he anticipate becoming a campaigner or public speaker about child sexual exploitation. “My job is to write news stories. I think the best way I can help is to carry on working as a journalist.”

He is not interested in becoming a star or a celeb.  That is also not being biased.
^