I don't think the division line runs on the open-source software front here. Windows has historically offered some of the most stable APIs, meanwhile there's plenty of examples of popular open-source software with a lot of breaking changes.
The comment you replied to said "significant portion of" and I believe it is clear which portion that refers to: the culture around c, linux, vim and bash, not things like nodejs, java and (semi-open-source) elasticsearch which are culturally separate.
