As somebody who’s used to it, whether through observing people, myself or stuff like Encyclopedia Dramatica aggressive humour is what it says. It’s used at the expense of others. To give an answer, an Alabama person has a black friend which it sometimes tells watermelon jokes even as the latter gets pissed. The Alabama person never intended any harm and still is cordial to the latter at first though it explains how detrimental it is for others.
It might not be bullying but it’s not always a good way to tell jokes, especially if it’ll offend somebody like sneering black people using watermelon jokes. They wouldn’t like it much even if they can shrug it off a bit. As for the user, such humour seems influenced by negative sentiments that it’s embarrassed of. Even if the user admitted it honestly, it still resorts to sneering as if it hasn’t let go to the point where it might be projecting.
One could say that aggressive humour is tacit projection if anime fans ridiculing bronies are any indication.