I believe the question Powershell - changing the value of an environnement variable was incorrectly migrated to SuperUser.
How on Earth is this not programming or tool related? As far as I can see it is 100% on topic for Stack Overflow, and that is where it stands the best chance of getting a decent answer.
How did it happen? I think this was kicked off by a single user voting for migration, then three low rep (less experienced) users agreed (quite possibly because it made the Close Votes review queue), then some guy finished it off.
Could it get answered on Super User? Maybe. Should it be there? No.