Thank you for providing evidence in my favor by communicating an idea with words near the edge of incoherence. Obviously there's a spectrum here between near misses and totally breakdown of language. But this is Lemmy so let's jump the gun and not give people the consideration we would if we spoke to them to their face. I'm talking about how all the examples people have been providing are near misses that are very clearly communicating the same thing as a "correct" word. People aren't stupid for using them, you're an asshole for being irritated by it
Genuine answer: because it makes language less accurate and if you have to infer what the other person is trying to say (instead of what they are actually saying) that is just unnecessary energy wasted and it WILL create misunderstandings eventually.
Disclaimer: I know this is about accurately using language, but as English is not my first language, this comment might not be entirely accurate itself, lol. But I am observing similar situations like the one this post is about in my first language (German) as well