Holier than thou

At my last contract job, building a gloriously swift website in Drupal, I decided to give generously of my generous contract income to Free Software.
Notepad++ is my perennial Windows text editor of choice, even in the light of the oncoming (proprietary) text editor juggernaut that is Sublime. And I decided to give, as it was my constant companion in the weeks that I was there.
Now I'm not speaking vast sums, maybe about $20 or $30. But a bit, to support the main man Don Ho. Two other developers on the project also use Notepad++, every single day, so I asked them if they'd like to make a contribution too.
Uh oh, big no no.
For those that don't know, being a web developer isn't the worst paid job in the world. So I thought they may at least entertain the idea. But no, not at all, not even a smidgin, not one dime.
This puzzled me, I don't know why they wouldn't give. I didn't pursue it, like some long-haired communist hippy type. I was just a bit puzzled, and I still am. Free Software isn't something for nothing, after all.