My favorite example of this.

Hint: George Lucas has stated in the most plain-English unambiguous terms that the empire does in fact represent US imperialism in A New Hope. It’s in a director chat interview thing with with James Cameron if you feel like searching it up.

The A.V. Club used to do a series where bands would come on and choose from a list of songs to cover. As the season goes on, the list shrinks and the covers get more exotic. You can search “av undercover” on YouTube to watch through the back catalog of old seasons for some pretty great covers. I don’t think they do it anymore, but it ran for several years.

Any content that was produced with the primary intent of making people angry.

Problem is that’s really hard to identify unless you know the original author’s intent. Just because it makes someone angry doesn’t necessarily mean it’s rage bait, but if it was explicitly made with that goal in mind, that’s what I would describe as rage bait.