I agree with you on your point. To clarify: It’s not that I would only contribute to CS projects, it is that I’m not a JavaScript guru (I’m more of a devops/data warehouse/automation creature). I see CS as a tool that enables others to create clean & functional JS, is easier to read (opinion), and would provide an easier entry for me as a contributor.
Though come to think of it, it seems there are other barriers to contributing to open source other than the language itself. Contribution processes, Git pull requests, anxiety around being publicly chastised for janky pull requests, etc. 
How about streamlining the contribution process? Seems like there could be an opportunity here for some interesting open source development as well… a “GitHub” like service that manages contributions, integrates with github(others), and makes the contribution process more welcoming for developers who may be coming from varied backgrounds.