You're seeing phones from vendors that have tacked their own stuff on top of the Android platform. Buy a Google phone and you'll find no cruft. There are still things you can't uninstall, but they're mostly essential to the functioning of the phone.
Google drive. Uninstall is "unistall all updates to this system app"
Google play movies and tv - likewise, essential?
Google play music
Google Hangouts
The list goes on...
And you're telling me the manufacturer decided I can't rid myself of these and google are as suprised as I am about that? Really? I mean you can make the same argument with Apple. They're happy for you to install/uninstall whatever but the manufacturer did it their way.
...iTunes is completely uninstallable on a Mac though?
The answer (as with most Mac-related things) is to disable System Integrity Protection. For some strange reason, most of the people who complain about the loss of their freedoms on macOS leave SIP enabled and I wonder why.