"AI" can mean anything with machine learning. Spellchecker can use some sort of machine learning too. But what people mean when they say "AI" is LLM chatbot. But a spellchecker highlights mistakes, it doesn't suggest to rewrite the text arbitrarily like an LLM chatbot. So I totally understand how you can be for one and not other

By the way autocorrect on the iphone got worse recently, bunch of times it "corrected" the word to a wrong one for me