There are times, though, when doxing is nothing more than a bullying tactic. When it's used to shine a light on someone's supposedly anonymous ignorance and is a calling out, I approve. But when it's used to harass because their views differ from yours then I heartily disapprove.
This has a lot in common with leaking corporate secrets. When it's used for whistleblowing, to reveal criminal or unethical activity, then it can be a good thing. When it's used for personal profit, revenge, or any other immorality, then it's a bad thing. This is a complex issue, and people who wish to doxx someone should be damn sure that they're doing the right thing. (And people who perpetuate the doxing should be sure they check their facts as well.)
Consider that we have no idea if the guy in these screenshots actually said any of this shit. Screenshots are easy to fake, and fakes have been done before. If doxing becomes accepted practice, and people just forward the info without checking sources (and you know most people don't check sources) that just leads to irrational mob justice. Would you be okay with spreading this if you found out that someone was slandering this guy because they wanted a prestigious internship that both were up for? How can you know that those screenshots are real, and not the product of an angry ex, or someone he beat at Call of Duty?
I'm with Dave that doxing has a lot of potential for abuse. What if people you disagree with start doxing? What if rapists attempt to shame their victims into silence by doxing them? What about churches that publicly post pictures of people entering porn shops or abortion clinics? Easy for some feminist blogger to say "I don't care" when they're already a public figure, and the doxing doesn't change their reputation. It's a lot different when someone starts as an unknown, and the information posted could radically change how they are perceived and treated by the community around them. Imagine if the Westboro Baptist Church, instead of simply picketing funerals, started sifting through Tumblr and outing gay teens to their parents. Do you think those teens would say "I don't care" to people posting their personal information, with the intent to shame them for they've said online? Would it make a difference if they were college students, or even older, but still hadn't come out to their family?
There are reasons why the witness protection program exists, and why minors aren't identified in certain court proceedings (either victims or the accused). Privacy is a very important aspect of life. It's a concept with a lot of fuzzy areas where it's hard to tell right from wrong, and it's even fuzzier when the law is concerned, but it's not something that should be violated lightly.