
Well, I’ve heard guys talk about “ugly friends cockblocking out of jealosy”, which might be them projecting their entitlement onto friend groups that protect each other. It might literally just be entitled men who hate that they can’t just prey on someone because her friends are there.
From their perspective, insulting a friend is still an interaction with the woman they are hitting on, and therefore it could still lead to sex. Also, it allows them to protect their ego by being the first to talk shit. Now, if they get rejected, they kinda did it first anyway, in a twisted sense.