I'm guessing Libtard is too juvenile and lefty just doesn't sound insulting enough, but is 'Social Justice Warrior' as an insult seriously a thing? Why?!
Being Left isn't necessarily a bad thing. I support a number of policies and ideas which would probably be considered left of center.
First off, I love the sound of it. I love social justice and to me warrior denotes showing passion toward something. Given that the terms started off with positive connotations goes to show that there is nothing wrong with the wording itself.
Passion, yes. Another word would be zealous, as in zealots, as in violent, ignorant, hate-filled people who know virtually nothing about the things they're so 'passionate' about. SJWs ignore complexity and have a very narrow focus. To them, they're noble and supporting great causes. Anyone who disagrees with them is the enemy, who they seek always to silence and punish. Mao's Red Guards would be the equivalent of the SJWs today, in their mindset and violent 'passion', and their hate for heretics and 'counter revolutionaries'.
So I'm not surprised you identify with such people. You share their disdain and contempt for anyone who disagrees with you.