Generally I don't approve of doxxing and wouldn't want someone to do it to me. But if I got doxxed it wouldn't "ruin my life" because I'm not on the internet saying the Holocaust didn't happen and telling people to get back in the oven. Not to mention that the expectation of complete anonymity on the internet is just naive these days. So I don't really feel sorry for them. If you don't wan to get caught being a racist POS don't be a racist POS. I would and do stand by any of the opinions I post on this site in public.
The trouble with this is that the internet rumour mill will often misquote or outright fabricate transgressions if it helps "the cause". This isn't really confined to the left - it happens on the right, and to weirdly apolitical causes as well. I think the trend of doxxing as a "legitimate tactic" really is chilling, because mobs - from gamergate to those Tumblr pages that catalog people in culturally appropriative Halloween costumes - are by their very nature unforgiving and unreasonable.
I do feel sympathy for alt-righters who get doxxed, even the real dicks. I also feel the same for most anybody an internet hivemind feels pissed off enough at to target. As a tactic, it's harmful to society and - the key failing of any political tactic - doesn't really accomplish anything except allow people to reach catharsis.
The real problem is that nobody feels like they are part of an internet mob, and it's even easier to get caught up in it than an IRL mob (after all, you will never get punched in the face via screen).