Often it's because setting up a David versus Goliath story is good for business.
Spotify did this all the time where they would complain about Apple not allowing them access to some private API and then when they did didn't even bother to use it.
Nextcloud is about synchronising files. Some people may only sync media files, but surely you can imagine that others want to sync other files, right? It's not that crazy, Dropbox, GDrive, iCloud, etc. all do that.
Do you really think it seems unfair that a file sync app would want to access files?
Spotify did this all the time where they would complain about Apple not allowing them access to some private API and then when they did didn't even bother to use it.