Rather, they want to be able to say anything to annoy people as much as possible, for the kicks.
Verily, it's important to be able to say annoying things: try speaking about atheism or a different religion in a devout crowd (capitalism among the "left", climate change among the "right", etc). But the intention is important. The intention of trolls is to enjoy other people's discomfort, not to voice an important idea.
Unfortunately, this is very hard to formalize.