"Extremist" is just a pejorative variant of "radical". I assume they're using it tongue-in-cheek.
When it comes to speech, it's really not hard to imagine positions that would have been controversial at any point in the history of the US. That doesn't mean you can't hold them, but others don't need to agree, and that's how you end up with labels of this sort.
When it comes to speech, it's really not hard to imagine positions that would have been controversial at any point in the history of the US. That doesn't mean you can't hold them, but others don't need to agree, and that's how you end up with labels of this sort.