Apps can hook into the Apple TV user profiles if they want, but many don't.
As a developer myself, I respect and understand that it's not their fault that profiles are useless
As a consumer, I don't care whose fault it is that profiles are useless.
the developer needs to write code to detect the current profile. Most app’s don’t do this, and they explicitly ask a 2nd time. Not apple’s fault.
There are some apps that get this right. Infuse recently added support for this.