Yeah, macOS does not touch files in Pictures or Music, only files that you've explicitly imported into the Photos or Music/iTunes apps. And it definitely doesn't silently delete photos from iCloud, if that was common it would be a major bug that would make the news.
It's interesting to me how people can upvote comments that are pretty much made up nonsense but comments like yours and mine are downvoted because people just want to hate on Apple.
