This is one of the strangest opinions I've seen in awhile. Your complaint seems like it should be pointed at projects not having a working "clean" make target.
Also:
git status --ignored
git clean -ndX # preview what would be removed
git clean -fdX # actually delete the files (warning: destructive)
cxr · · focus · HN ↗
[dead]
athorax · · focus · HN ↗
Also:
[deleted] · · focus · HN ↗
[deleted]