If there are limits, its not free.
Absolute free speech, like the free market, has only ever existed in theory. In practice even most free speech absolutists are just quibbling over where to draw the lines of censorship and tolerance.
I think that much of this kind of stupid discourse on HN is driven by thiel-worshipping reactionaries who believe weird theories about why their genes make them better than black people, but another huge part of it seems to be literally fourteen year old libertarians. Which are you?