I'm not sure you've established the problem is the individual developers. Of course you can't provide all relevant information for diagnosing the issue in an HN post. I'm just making general suggestions.

I recommend that you rule out other possible explanations: (1) A former manager told them to always use a VM. (2) A CS professor taught them to do this and no one has instructed them to do otherwise at your company.

Coming back with the same question multiple times is problematic, but maybe you didn't offer a sufficiently clear explanation. Next time you explain something say, "Do you understand?" or "Was that clear?" Then you'll be able to say, "people like this" next time they ask the question.