The Isaac Foundation, which raises money for children with a rare enzyme deficiency known as MPS VI, says in its blog that the 32-year-old singer is a "kind, caring and compassionate person" they have come to "respect."
"I don't care what Playboy magazine writes about the man, and I don't care what John says to the journalists that write what they do about him," writes the group's founder, Andrew McFadyen. "In America, it's all part of the game."
Mayer has donated generously to the group and spent time with Isaac, the little boy with MPS VI, and his father McFadyen. Mayer met Isaac when the boy was 4 years old before a concert in Toronto in July of 2008. Mayer blogged that the little boy was "one of the coolest kids I've ever met."
"I know he has said things that turn people off. I know he's said things that make him sound like someone you would never want your children around – ever," McFadyen writes. "But I also know the person that he truly is and the good things he tries to accomplish with the celebrity status he's achieved."
Mayer has given Isaac's family love and a sense of "hope" that there is a cure for the disease, McFadyen says.
"Write what you want about John, think what you will, but before you hand down your verdict on what kind of person he really is, please consider the good he has done in his life."
In the fallout since his interview, Mayer had stopped his typically incessant Tweeting – but he recently broke his Twitter silence to link to The Isaac Foundation's Web site.