Weird thing at the end of the article (Can it not be both?), but other than that... hell, hell if I know. From what I've seen, we do try to excuse our inability to help others. It's... I'unno, one of those deeply hypocritical aspects of most societies I'm familiar with, where, especially when young, we're taught that helping others and loving one's neighbor and etc., and so forth, and so on is all important and good and crap, but apparently when we hit the point that it turns out that, hey, it can be pretty hard to do that shit so we start trying to figure out ways to not. And then we notice the methods other people around us (in our peer group, or elders) are excusing betraying those early lessons and just kinda'... join in. S'very natural.
Devaluing others is just one of those methods, I guess? If you can't or don't want to help someone who needs help, despite being taught that you ought to, well, obviously the problem must be in the one that needs help, right? You, yourself, can't be a bad person, after all... right? If you were willfully refusing to or unable to figure out a way to do the right thing, then you'd be a bad or incapable person, but you're not, so there must be something about them that justifies not helping. Even if there isn't. And so it goes. Lot of times it seems like it's not even explicit like that, just a kinda' subconscious heuristic people run certain problems they encounter through. "The fault must not lie with me."
But yeah, people in desperate straights turning nasty is... pretty standard fare. For whatever reason, that's pretty normal psychology for us monkeys. Awareness of the behavior is the first step towards avoiding it.