Not legally, nor morally.
Morally we can argue that there's virtue (or a lot of global positive utility if we use an utilitarian framework) in making sure that there's an open marketplace for ideas, and every idea has opportunity to be "priced". But there's also virtue in keeping that place healthy, sane and constructive. Hate speech, manifestos, slur memes, and other kinds of low-effort content seems to be rather unhealthy for the place.
While at the same time doing a proper academic study on intelligence, brains, genetics, education, socioeconomic status, social mobility, and group dynamics at large is healthy. Context, style, framing is important. Blurting out that "blacks" have lower IQ in some measure might even be true, but that's not really an idea for that marketplace. Connecting the dots, uncovering the causes, the dynamics (noticing that the main driver is not some inherent genetic/cultural inferiority, but simple socioeconomic status due to historical path dependence) - and raising awareness and offering solutions is healthy.
Yes, of course, it's upon us to make a value judgement about what's a virtue, what's healthy. And no wonder some people think that even adopting the Golden Rule (do only what you want others to do, see also Rawl's reflective equilibrium) just means we have to "purge the weak" and that "civilizations are destined to clash". Of course we can't do much with that, other than trying to persuade them AND trying to minimize these voices so they remain a weak but vocal minority. (Hence our choice of idea policing is not just because we happen to think equality and pacifism are virtuous, but because our survival, way of life and so might depend on it.) [And in that way, yes cultures are destined to clash, and we ought to think a pacifist-equalist is the one that should win - nothing to do about it, another value judgement to make.]