Almost certainly not. Just like click-through terms (terms that are offered only by link with an Ok button) are not enforceable. It’s just there to dissuade those that assume it has any weight, which isclikely most people that are not lawyers or filthy rich who would consult a lawyer anyways if they got hurt.

It’s almost certainly on similar legal grounds to a cease and decist letter. You’re not being sued, you’re just being warned that they don’t like you via legalese.

Depends: how poor are you?

It probably isn’t legally binding, but is enough to get most folks off their back.

No, but they can use it to drag out the court case until you run out of money.