Its like white people telling brown people that airport security isnt a toxic place and its all in their mind. Things are toxic...just not for everyone. Try being colored or not part of the in-crowd on Twitter and you get to see how toxic it is.
The point of twitter isnt just to read, but also to engage. But engagement is hard when tiki-toting nationalists are sending death threads to anyone that doesnt want to turn the world into prison.
Even technical (non political) conversations get all sorts of hate flung at PoC accounts.