I think in those cases, even if the do-gooder is gloating, you are 75% in the wrong. It's also a social contract, do-gooder does good and gets to gloat, you hate them for it but let them gloat because you are relieved someone else did the dirty work.
If there were no do-gooders (as opposed to trouble makers and busy bodies) in the world, we'd be even more screwed than we already are.
Social workers get a bad rap because they are simultaneously viewed suspiciously as an agent of "the man" and as a scapegoat for not single-handledly solving the problems of poverty, racism, and discrimination and not being even more of a martyr than they are.
Also, let's define 'do-gooder'. There are those whose PERSONALITY you LIKE and those whose PERSONALITY you DON'T LIKE. There are those who METHODS you APPROVE OF and those whose METHODS you DISAPPROVE. And there are those whose INTENTIONS you BELIEVE and those whose INTENTIONS you DON'T BELIEVE or LOOK DOWN upon.
As far as 'environmentalist' or 'animal lover' there is a HUGE difference between PETA and the ASPCA, between people planting trees, people living in trees to prevent clear cutting, and people blowing up SUVs to save trees (?)
So basically, lots of reasons to hate people.
Personally, I'm a lover, not a hater.
Actually, I take that back. I'm not a lover, or hater.
I'm a napper.