Are some bigoted people evil? Sure. But I think that a lot of people hold various opinions because they just haven't thought about it too hard. They've just gone along with whatever they've been taught from childhood, and they're just kind of parroting their indoctrination. That doesn't make them bad.
Unfortunately, the SJW crowd (to be distinguished from the mostly rational leftist crowd) seems to have decided to elevate themselves based on their enlightenment. "I've devoted the time to make myself more informed, and that makes me a good person." With that black-and-white thinking comes the inverse - you're a bad person because you haven't devoted this time to make yourself more informed.
Such thinking immediately makes people bristle and walk off. Why would they volunteer for abuse? I don't talk to SJWs because it's ridiculous to be treated like subhuman filth for disagreeing with something that the other person treats as Gospel, especially when a huge amount of this material is hugely complicated and up for debate.
The guiding principle should be stop being an asshole. Instead, the SJW crowd resorts to yelling about "tone policing" and drives away people who would normally be allies.
Here's some food for thought. The black civil rights movement in the 60s and the gay rights movement today have enjoyed a lot of success because they emphasized their status as normal people. As soon as you get the kooks who excoriate people for any slight deviation from the One True Faith, you end up failing miserably.