Depends on how much of a threat they are. Some random loser on /pol/ who will never leave their basement in order to harm anyone is probably not worth punching. But someone like Richard Spencer, who has a lot of reach and influence as a big name, I’ll gleefully watch that one clip over and over with popcorn at the ready.
I suppose the more difficult question to ask is where to draw the line in between.
Normally these kind of announcements come with some kind of explanation. The lack of one reflects very poorly on Mozilla and leads me to assume the worst.