As you are clearly blurring the lines between this specific issues and a more general one, I'm going to reference the latter and exclusively the latter. There's a wide gulf between pedophilia and then jumping into appeals against the ever more amorphous 'hate speech.' So on that note it's interesting that in the early 20th century if you look at support in the US for eugenics it was practically a who's who of academia: The Carnegie Institution, Rockefeller Foundation, W.E.B. Du Bois, Harvard, Stanford, etc, etc. [1] One might argue that such views were "purely racist, hate-filled viewpoints." The very reason freedom of speech was such a revolutionary concept is because authority figures, since time immemorial, have been able to propagate bad ideas and manipulate the general population by making false statements which could not be challenged.
In contemporary times a good example of this is Iraq. Our invasion was precipitated based on fabricated evidence and appeals to authority of the sort 'x intelligence agencies have proven beyond any doubt that Iraq has or is pursuing nuclear weapons of mass destruction.' After the fact when an individual [2] tasked with investigating whether Iraq was or was not trying to purchase uranium (he found they absolutely were not and reported as such - the government would go on to claim they were trying to purchase uranium), a government official outed his wife as a covert CIA operative (which the Washington Post would go on to publish) not only potentially endangering her, but terminating her career.
In the case of eugenics it wasn't so much a conspiracy rather than that authority and academia were simply collectively wrong, as has also often occurred. Censorship benefits those in power and only those in power. Those in power choosing to try to inhibit censorship, as happened with the first amendment, was quite the revolution! The point of free speech is to ensure that not only with the good comes the bad, but also that with the bad comes the good. When you begin to tolerate censorship by one side - you very much risk that the side doing the censoring is the bad. And in efforts to obtain only the good, you end up with only the bad.
In today's world, free speech and corporations are becoming a major new issue. An ever larger percent of all human communication is digital, and digital communication is extremely monopolized. This means, for instance, that the US government could effectively circumvent the first amendment by simply pressuring a single company rather than passing a law against the dissemination of any given viewpoint. It also means that a very small handful of people could end censoring or otherwise manipulating public discourse for billions. That is exactly what the first amendment sought to prevent; only the founding fathers could never have imagined a corporation (under which two people have majority control) having more power over speech than any government in the world.
[1] - https://en.wikipedia.org/wiki/Eugenics_in_the_United_States
[2] - https://en.wikipedia.org/wiki/Joseph_C._Wilson