Why do I have to keep "signing in?"

Every time I rent a movie on Apple TV, it asks me for my password. Why? Is there a secret way (because I've not been able to find it) to turn this off? It is very annoying, such that I have stopped renting movies from Apple. I can just go to Amazon and just rent a movie, no password to sign in every time. The only time I will use Apple and then have to enter the password is for 4k movies. I know some are going to say, "it's not big deal to enter the password each time," and that is true, it's just why? Other on-line movie renters don't do this and the world has not ended. My two cents.