I don't think anyone claims that "X is stupid" is hate, regardless of how broad or nonsensical X is.

X should die, or X are vile subhumans stealing our jobs, or we should rape X, or X are raping our dogs is hate.

Do remember that something like 'fossil fuels are destroying the environment' would be called 'hate speech' if power shifted a bit. 'Hate' is an emotive term used to bypass peoples thinking so that criticism of certain things can be disposed of by emotion rather than evidence. People bringing up evidence of malfeasance could be called 'hate filled' people, have what they say aggressively censored, so that other people only hear these are 'hate filled' people and what they say be buried so that inconvenient information doesn't come out.

There's an expression in my native language which, directly translated, is something along these lines:

"If my grandma had a rotor, she'd be a helicopter". I think it perfectly encapsulates your "slippery slope" argument, that if today we accept that saying you want to rape someone on Twitter is hate that needs to be stopped, tomorrow saying that processed foods are bad will be hate as well. Do you even realise how stupid your argument sounds? We're not talking about criticism. Were Nazis "criticizing" Jews? Do racists "criticize" other "races"? No, they hate them, and there is a pretty heavy difference between the two.

> Do racists "criticize" other "races"?

The word "racist" seems to have a thousand subtly (and not so subtly) different meanings depending on who is using it. I think this is a good example of the phenomena.

Do you think it impossible that someone could believe that Chinese people are more intelligent than Nigerians due to genetics without hating them? Or do you just think said person would not necessarily be racist?

Yes, another way to discredit someone with a valid concern is use name calling as the basis of their argument, just like what the parent post does here. School yard bullies used named calling to socially destroy the reputation of their victims and isolate them. Adults use the same name calling to do the same thing, they just use different words.

I have definitely seen "Muslims are stupid" be called hate speech.

Though you might have different standards... Would you say "So called transwomen are not women!" is hate speech?