It's just, we had decades of wars and (justified) propaganda that thoroughly discredited fascism and their style of racism so it's easy to see how the right extremes is bad.
What the extreme left is doing on the other hand is a more modern variation of racism and totalitarianism. It's ostensibly driven by noble concepts like social justice but in reality devolves into racial discrimination, dogmatism and tribalism as is seen on far right, just with a different dogma and different racial preferences.
Maybe you find that particular dogma more agreeable, or maybe the ends justify the means for you, I dunno.
But if you genuinely look at the discussion on Twitter or Reddit and you don't see extreme left views upvoted as often as extreme right I don't really know what to tell you. I guess people on the far right don't recognize their own crowd as an extreme either, it's just normal and common sense to them too, dismissing any rough edges with the same excuses.
You want specific examples? Try being public about not fully supporting BLM. Not the literal slogan itself, but parts of everything else the movement and their leaders come with. See if anyone catches the nuance of your opinions as you're branded a racist for not falling in line. You don't even need to say anything racist, even a modicum of doubt in the dogma is seen as dogwhistling your obviously racist views.
Do you see a lot of sexism or racial slurs / offenses in what you personally read on the internet? I don't, but the parts that I frequent what I see are mostly leftist racism and sexism, blaming white people for what other white people did, generalizing straight white men as privileged, "sounds about white"... No, none of that rings a bell, or none of that sounds bad or important because <reasons>? Try switching white to black and see how that holds up. Feeling righteous and having noble reasons for racism and sexism doesn't make it right. That's how all racism is justified and never in history has it been the right way to go about treating people.