That is nice thing in my opinion. If you earn in next 5 years some big amount of bitcoins, it would be nice you to donate also. But now I'm talking about big earning. Like to buy 10 btc now (that is 4, 400 $ ) and to sell it for 20 000 $ each for like 7 years. Why not do donate couple thousands here, where you learned almost everything you know. And for sure on this place you find work to earn money to buy that bitcoins.
As I saw part of that money is used for this form to work properly, to not have problems. Someone needs to do million things for us here, so we can use this forum for learning and earning. Why to not have some salary?
It's a good thing, one day if I make big money I will also donate. But it is a very big "if", I'm working on it.