Just because it's true doesn't mean it isn't misleading. Consider if they had the same title but only analyzed projects with a single contributor or pet project

Just because it's true doesn't mean it isn't misleading. Consider if they had the same title but only analyzed projects with a single contributor or pet projects. By only including open source projects they've limited the ability to generalize their conclusions, which they themselves allude to in their "threats to validity" section. Changing the title simply better reflects the content of the article, which the researchers didn't do (sometimes this is due to external pressures such as university PR departments, but I doubt is the case here)