That's because open source tools are way better for software developers.

I find quirks or bugs or limitations in my tools all the time, and when they are open source I can fix and augment the tools however I want, and I can share those changes with others.

I can't do that for closed source software.

Now, for most software users it doesn't really matter because they couldn't fix a bug or add a feature anyway. Closed and open source are functionally equivalent, and it makes more sense to pay for support and not care you can't change it yourself.

I think this is kind of like cars; people who work on cars want to buy a car that doesn't have a bunch of electronic and proprietary parts that can't be worked on in their garage. On the other hand, people who won't work on their car anyway don't care.