Historic revisionism as an subgroup of hate speech is a prime example of slippery slope and moving of definition. I would add "fake news" to hate speech.
https://en.wikipedia.org/wiki/Media_bias_in_the_United_State...
The problem is the political spectrum of journalists is wildly biased compared to the average citizen. This also apparently shows up with censorship of phone apps.
I feel that when it comes to Google its not about if it is hate speech or not, but who controls it. I.e. Zuckerberg is fine although there are multiple long-lasting Facebook groups that have been used to incite crimes, but Aaron Swartz would not be (today). It is quite amusing how Facebook is not shut down in Europe even though many European countries would shut down any local company being so lax and arbitrary with moderation as Facebook.
What are you doing? Are you trying to ban speech you don't like? What body determines what is "fake news" and "hate speech"? It can't be done, which is why the only sane policy is free speech.
We have laws against violence, and it's a very clear line.