I worked for 13 years on open source software and I definitely did it to make money. Nothing wrong with trying to make money on open source software, it's just a different business model than proprietary. More consulting oriented than product oriented.
Nothing wrong with making money on your work, and if you work on open source, even better I think. I have been spending hours a week for decades working on FOSS, never got paid, so yes, that was (and still is) intentional charity.
