Thing is, had GitHub done nothing, there's no discussion at all right now on HN about how little they're doing.
But because they put $500k toward those people whose projects they rely upon, there is now a discussion of what a pittance it is (whether or not you append "good job, hopefully you do more in the future" doesn't change the critical tone you set with all your other words you said before you said that).
The lesson: Almost no act of generosity goes without criticism on social media or discussion sites.
(Note: I hold a pragmatic view of generosity. I don't care what a person or company's motivations are for being generous. PR? Great! Let's show it makes for great PR to be generous! Selfishness, bolstering one's sense of grandeur? Great, feel whatever you want about yourself, as others benefited! Trying to out-compete a rival or friend by giving more than they? Great competition to be in! Did GitHub give to one person? Great! Did they give to 900 people? Great! Did they give each person $10? Great! Did they give each person $550? Great!)