These people are farming contributions to major FOSS projects as a form of CV-padding. The same is happening with vulnerability reports. The sloppers may genuinely think they're helping out, or they may know their 'contributions' are a net negative for the projects, in the end it doesn't matter much. When you're motivated by direct economical incentives and your situation is precarious enough (in today's labor market, it is), externalities are not high on your list of concerns.
Developers who have a nice job and career, and are making good money, might think of doing open source to “contribute to society” or something like that.
But new developers who are seeing those golden opportunities shut in front of their faces, they feel like they have to desperately fight for the last places on the lifeboat, so I don’t blame them for wanting to farm cv points and game the system of incompetent recruiters who make much more then they will do, instead of spending time and effort doing something nice for society hoping someone will notice (lol they will not, especially if you’re a nobody)
Who the hell is looking at someone's "documentation cleanup" GitHub PRs and using them to boost their job application? I've served as an interviewer at every job I've worked and none of them tell you to even look at the candidate's GitHub, let alone allow its existence or nonexistence to influence your appraisal.
They can even list on their CV that they are the maintainers of those projects.
I do think I helped out.
And I have discovered this edge case when fiddling with my homelab which is my hobby.
Both PR were tiny, not different from human PR. I still believe these were valuable additions, and obviously some maintainers think the same.