Simply allowing people to see your code doesn’t give them any rights to use it. OSS provides a license that allows you to use software without paying the creator, that’s the donation.
As to being a maintainer, if you’re using that code for something and updating it whenever you personally have a problem that’s still a maintainer. Consider a geologist who created an absurdly accurate GPS for exactly the hardware they have. If’s it’s working for them they might go years without making an update, and that’s fine. Someone saying there is a bug when used on farm equipment simply is’t their problem. Even a different geologist seeing issues south of the equator isn’t their problem. The software is free and almost sufficient, feel free to pay someone if it’s not doing what you want.
The core issue is OSS is free to use and modify, but that also means the maintainer is free of all obligations.
I do not think anybody is making the _legal_ argument that consumers of publicly available software with an associated clear LICENSE file are granted any additional rights. Open Source is much more than what you are suggesting. It's like saying all there is to soccer/football is <first degree technical definition here>.
Just like most things, there is a very important and obvious people/social dimension on top of that.
It's not entirely surprising this is a problem in our industry. After all, Software Engineers are most definitely NOT known for their social skills. The emergent properties of human interactions over time is a very complicated problem.
I think you’re confusion is around the most well known OSS projects which try and increase adoption and generally request donations. That’s a relatively small chunk of the overall OSS community which is well known specially because maintainers have a personal desire or financial incentive to increase adoption.
Far more often projects are released as OSS because sharing a project is a net benefit to the world and costs the donator nothing. That’s really the central idea of the OSS movement, when copying is free it’s easy to be generous. Forcing a social obligation is therefore toxic to the OSS community as releasing software becomes expensive.
As to being a maintainer, if you’re using that code for something and updating it whenever you personally have a problem that’s still a maintainer. Consider a geologist who created an absurdly accurate GPS for exactly the hardware they have. If’s it’s working for them they might go years without making an update, and that’s fine. Someone saying there is a bug when used on farm equipment simply is’t their problem. Even a different geologist seeing issues south of the equator isn’t their problem. The software is free and almost sufficient, feel free to pay someone if it’s not doing what you want.
The core issue is OSS is free to use and modify, but that also means the maintainer is free of all obligations.