It's felt somewhat unique to WP for sure, though maybe there are other examples where swaths of communities get big mad when people suggest distributing GPL software for free. I found it a little repellent, but lots of folks scraped together micro-scale businesses selling plugins and themes.
I believe I made a lot better living building stuff for clients and then not caring about what they did with the software, but hey, I'm not the boss of folks trying to make a living supporting a $10 lifetime membership to an image size selecting plugin.
Anyhow, my point is that there is at least a little nuance to be found when thinking about WP and open source software.