I encounter this in real life as well as on After hours

People who have a
problem with other people either doing charitable work or donating to charity.
Firstly giving to charity. There is apparently a right and a wrong way to give to charity. If you give to charity as it makes you feel good, well thats just not right. I've no idea why. The begrudger attitude is that you should feel downright miserable after donating.
Calling someone a "do gooder". This is an ingenious insult. People call Bono a do gooder. It literally means "do good things" yet is meant as an insult! Is anyone else amazed by this?? Imagine if you insulted a soccer player by saying "Oh he just scores goals" or a businessman by saying "He just makes lots of money".
People who don't give to charity or do charity work seem obsessed with the "motive" of people who do. Adi Roche has done some fabulous work with Chernobyl kids yet the focus is on whether its just to make herself look good. It might be but what difference does it make?
I'm curious, do "do gooders" make people feel guilty? Is the begrudgery an attempt to allay that guilt?