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.