It's pretty rude to "accuse" someone of using AI. Would you yell "Dictionary!", "Grammarly!", "Reference manual!", "Newspaper quote!" at them? Maybe "Harvard!" or "Tutored!" ? You don't know who they are or what their life is like. Maybe they're blind and using it as an assisted device. Maybe their hand is injured and they use it to output information faster. Maybe they're old, infirm, a non-native English speaker, etc. Maybe they're just a regular person who feels insecure writing, and wants to use new technology to give them the confidence to write/comment more. Or, maybe they just talk like that.

Let's say you happen to be lucky, don't accuse someone unfairly, and they are using ChatGPT to write what they said. Who cares?! What is it you're doing by "calling them out" ? Winning internet points? Feeling superior? Fixing the world?