"suddenly that no longer serves a narrative the left wants to tell"

Except that that was also reported mostly everywhere. Also, one sided 'evil-looking' harassment is news that is more interesting to most people because it might signal some trend. No-one (left or right) would have found a word-fight between evenly-wrong grey characters very interesting if that was the story in the first place. Because it just isn't.

That doesn't make the mainstream press left-biased. I think it actually isn't.