You didn't get negative comments just because deleting posts, you got negative tag for deleting negative comments , instead properly answering to them.
If you are running legit organization, answer these accusations and provide some proof, but instead you opted for deleting comments. And if you can't give proper proof, then you will be consider as scammer.
It wouldn't be the first time that someone here is pretending to be from some organization and asking for charity, while running a scam.