>>11790
They can afford to be rude and aggressive because they are also a powerful cultural force. The assumptions that underpin the arguments of social liberalism and everything to the left of it is that they are helping people live better lives, or striking at people who hurt others, so they are easily able to portray their opponents as uncaring or mean, or outright evil - and it's alright to be vicious to evil-doers.
Besides, their tactics only serve to whip up the base, those who already agree with them or with their basic assumptions. It doesn't win any friends - if you look at the SJWs, and the split they're causing, you'd know it's not a good tactic for the long-term as you must eventually find targets everywhere, even among your allies. Libertarians and fiscal conservatives have less broad support in society, so we must portray our side well or we simply fall into the trap already set for us - that we are mean, uncaring people.
Also fuck being a nasty a person in general. The golden rule, baby - do unto others as you'd have them do to you.