Trump wants the oppsite actually - platforms not to moderate it. Not that it is any of his business this way or the other.
Which is the actual goal.
And to be honest, racism and <insert-color> supermacy are the most primitive & superficial form of collectivism and thus disgusting, but...
If the idiots on left are going for affirmative action, which is basically discrimination based on superficial qualities such as gender, race & religion, why the idiots on the right should not be allowed to do the same?
It's quite possible that some people who want free speech now might be against free speech for others, but that's hardly an argument against having free speech in the first place.
It's an interesting thought experiment: under free speech you should be free to advocate for a restriction of free speech.
I'm questioning the idea that if all platforms were to be less restrictive, that particular type of content would become "overwhelming".
Some communities are more active online than others but generally I would expect the distribution of opinions expressed online to reflect the actual distribution of opinions actually held by the population.
You're assuming most people are tolerant of racist and bigoted content and don't mind seeing a constant stream of it, but when the Nazis show up, their discourse tends to drive everyone else away if they aren't banned. That's why they tend to take over communities where, in theory all sorts of opinions are welcome.