Sure, people can do anything. As a person/citizen/voter I would probably vote against using tax dollars for open-source work. I'd prefer a less convoluted and more honest approach. Doing something for free and then complaining about not getting paid for it later is super cringe and passive aggressive regardless as to whether or not "greedy people" are using it.

Being an open-source maintainer is just some thing people decide they want to do. There's nothing special about it. If you want to get paid, figure out that arrangement for yourself. If you want to do it for free and give it away because you love it, that's great too. That's what free association is all about.

Taxing me to pay for other people to fund their hobby seems ripe for 2 bad things: 1. if the government is funding it, the government gets a say - doesn't bode well for open-source, and 2 it creates market inefficiencies in a bad way - we fund thing we shouldn't fund and we do so to support a lifestyle or hobby instead of what is truly economically valuable for all.