if i punch you in the face then you should ignore it
I talk to you across the room, you pretend like you didn't hear me. I talk to someone else, they do the same. I get bored and leave because no one wants to talk to me.
Getting punched in the face would be like him hacking, doxing you, or something bad, that requires a direct confrontation. Here you are giving attention, which gives him more reason to stay and argue with you guys. You are basically anchoring him by giving him all this attention.