In order to write good fiction, especially good romance, you have to be able to (mentally) put yourself in someone else's shoes. You have to imagine exactly how things -- things said, things done, etc -- will make characters feel and react. Characters' emotions are integral to a good romance. Without emotion, readers won't connect with your characters, won't care much about your story. So, many writers spend a good deal of time imagining how things will make others feel. And it's not like you just shut that off when you stop writing. I think many writers spend more time than the average person considering how their own actions and words will affect others in real life, too.
So, IMO, this means that writers in general are probably more likely to give a damn about the way people are treated and about things they perceive to be wrong or unfair / social causes. Considering how one's words / actions will affect others also generally causes one to treat others more nicely...
And I've met a lot of nice writers. When I went to RT last month, I met so many nice people, I was actually surprised. Seeing as how I was going for the first time and had literally never met anyone there in real life before (just a couple social media connections) I'd thought it might be a challenge to meet nice people to spend time with. That wasn't the case at all. Most of the people I met were delightful and treated others well.
Of course, there are always exceptions -- there are sour apples in every bunch, and at one point I encountered a group of nasty, mean-spirited attendees in an elevator. I glimpsed at their badges and saw that they were aspiring authors though, so for all I know, they were maniacs who spend their time writing Axis alliance fanfiction. Okay, probably not... But they were an exception to the rule when it came to the sort of writers I met.
Anyway, what's the point of this post? To invite you to something I (and a lot of other authors) give a damn about. Tomorrow is International Day Against Homophobia, and the starting day of the Hop Against Homophobia (which runs 5/17 - 5/20). There are about 250 participating authors. Here on my blog I'll be talking about homophobia (which is something I think is really unfair) and sharing some of my own experience. I'll also be giving away some awesome prizes (if I do say so myself). Hope to see you here! :)