Pfft next on your slippery slope you'll be making silly predictions about adverts in ridiculous places like the Start menu on Windows computers.
[1] : https://www.bleepingcomputer.com/news/microsoft/microsoft-is...
Obviously you should never pay for a device where they won't support you, the owner, unlocking the bootloader, but obviously people do. I'm not sure if Xiaomi are one of the manufacturers that do not support it.