This is just my own personal view of Free Software and why I write it.
Because you can and because it is fun.
It is math; it is machinery; it is ideation made concrete. Unless printed ("hardcopy") it exists only as patterns of light/electrons/magnetism and human thought.
Crucially, the "marginal cost" to duplicate such a pattern, once written, is so close to zero as to be effectively immeasurable.
I've been doing it for a quarter of a century and I'm barely competent. The vast majority of the people I've worked with who were paid to write software were worse (often much worse) than I am. Only a handful of people are capable of writing good software.
The right piece of code at the right time and place can make (or save) lots of money. It so happens that the person who wrote that code will not receive any of the value created in the vast majority of cases. Typically, you have to work as hard as Bill Gates and be as lucky to make anything like the value of a given piece of code. Most of us programmers are doomed to never see the true value of our software in any direct "bottom-line" way.
I figured this out long ago: no single company could ever pay me what I'm actually worth. They don't even try.
It occurred to me that the only way to efficiently benefit from my coding activites would be to give away the software and just enjoy the general economic benefits that would accrue to the whole of world society.
In the event, my idea has proven to be naive. The wealthy and powerful can take better advantage of the tech than the poor masses, and so (with some exceptions) most of the global elite are taking the gains and keeping them. I don't know what, if anything, to do about that.
I'm still going to give away my software for free, and under Free license, because it feels venal to charge people for copies of already-written software. It no longer feels like an important political consideration. The vast majority of people seem content to be serfs under the total control of one or more technology corporations. They complain and keep using the stuff. Again, I don't know what, if anything, to do about it.