you cant do that

so to my friend i was like dude thats gay
and then this random girl overheard me and was like can u plz not say that >:[
and i was like y lol
and then she was like its offensive to gay ppl
and i was like but i wasnt talking about gay ppl
and then she was like you described something that was bad as gay
and i was like yea lol
and then she was like thats offensive to gay ppl
and then i was like but i changed the definition of gay to mean bad, not homosexual
and then she was like you cant do that