Ad hominem (Latin for 'to the person'), short for argumentum ad hominem, refers to several types of arguments that are fallacious. Often nowadays this term refers to a rhetorical strategy where the speaker attacks the character, motive, or some other attribute of the person making an argument rather than the substance of the argument itself
The ad hominem part is specifically trying to discredit your arguments on the basis of an unrelated trait. They're making no attempt to do any such thing. It's rude, sure. But there's no argument in there. Read the examples in the wiki.
Ad hominem is more like whining, "you all downvoted me but didn't reply," with the implication that the position is correct because of their actions. "Shut up," isn't an ad hominem, it's just rude.