> That strikes me as the right thing to do
Yep, and it's there for very goos reasons. However if you don't know about it, it can be quite surprising and challenging to debug.
Also it's annoying when your phones permissions optimiser runs and removes the location permissions from e.g. Google Photos, and you realise a few months later that your photos no longer have their location.
There is never a good reason to permanently modify my files, if that is what is going on here. Seems like I wouldn't be able to search my photos by location reliably if that data was stripped from them.
Nothing is "permanently modifying your files".
What happens is that when an application without location permissions tries to get photos, the corresponding OS calls strip the geo location data when passing them. The original photos still have it, but the application doesn't, because it doesn't have access to your location.
This was done because most people didn't know that photos contain their location, and people got burned by stalkers and scammers.