The accusation of “racism” even directed at the argument and not the person is just a lazy style of argument—but that laziness isn’t even good enough, we need to go after the person.
It is no different than the lazy style of argument of those on the right calling everything socialism. Pretend that instead of a strong left wing bias on this board it was flipped. Instead of having a robust debate on universal healthcare, let’s say, posters would just should down the opposition as being socialists and Pit them for being socialists and demand that “we” as a “community” out the socialists because look at what we fought the Cold War to win.
Plus, as Sam Stone said and you hint at, the accusations of racism by posters on this board have nothing to do with racism. You think that a holiday to celebrate the end of slavery should be on a different day? Racism. You disagree with CRT? Racism. You agree with a 6-3 Supreme Court opinion on voting rights? Racism. You think the Chauvin verdict was a bit too much? Well, it’s only because you hate blacks and could not possibly be for any other reason but racism.
In fact, there is no debate. The left is so unquestionably correct, that any opposition must be racism. It’s the go to insult to shout down opposition so as not to have any real debates.