Those aren't needed to generate a hash of a file. And that metadata isn't part of the file itself (or at least doesn't need to be), it's part of the filesystem or OS
That's an acceptable answer for the simple case when you distribute just a file, but what if your distribution is something more complex, like an archive with some sub-archives? Metadata in the internal files will affect the checksum of the resulting archive.
unless you fix them to a known epoch.
Finding and fixing cases like this are part of what the project has done...