It's better to just ignore, fam.
Most of us let them talk and then overpower them with other things that are not related. Kinda like a
Person A: -says something crazy-
Person C to G and D: Anyway, bruh, have you seen Infinity War???
Silence is often your best bet. So if and when they reply, just keep it walking. No sense fighting on the internet against someone you more or less will never meet. Especially when that someone always has a complaint when they post, instead of posting about something good that's happened to them.
Keep that positive energy!! 