I just assumed it was the favored "dismiss 'em" label these days, used by those on the left who seem unable to debate anything without resorting to one or more of of many logical fallacies. I have no idea what it's actual meaning is...or if there even is one.
That's kind of the way it seems to be used to me - that there's Republicans - you know, the ones that capitulate to Democrats all the time - and there's those "extreme" ones who actually stick to what they believe.
EVER EVER hear the mainstream media refer to extreme progressives, extreme liberals, extreme left-wing? They don't, because the word "extreme" itself is used in politics to denote - "bad".
IfI said we had an extreme workout - that would be great but exhausting. An extreme ice cream sundae, that would be fantastic. Use it in politics and it's automatically suggest that it is *bad*. And extreme is anything they don't like.