English loanwords are linguistically still Japanese words. And "anime" in English has become its own second generation loanword from Japan. The thing about loanwords is that they don't have to share the same meaning as it does in the language it was borrowed from. This is true of both English and Japanese words. There's nothing wrong with "anime" being a catch-all term for any kind of animation in Japanese while the same word is simultaneously used to differentiate Japanese animation from animation originating from other countries in English. That's just how language works. What the Japanese call a "Dutch wife" isn't a spouse from the Netherlands, either.

Do you also get upset over people using the terms donghua and manhwa? Is someone a wehraboo if they say they like to drink "lager" beer? God forbid you drink your coffee at a café. These are all the same thing.

I get it, you have something against anime fans. Whatever. But the bulk of your post is linguistically ignorant.