if i had to take a guess, i'd say that helping others before helping yourself is considered a "good" thing, or makes you a "good" person. so, by that logic, helping yourself instead of helping other people is a "bad" thing, or makes you a "bad" person.
it's funny, though, since if we were 100% selfless, nobody would survive. and anyways, nobody is a saint. we're all "bad" in some way, shape, or form. it is nice to help others, even when there's little benefit, but acting as if people should be 100% selfless is setting your expectations too high.
(just realizing how much i put good and bad in quotes. oh well.)