How come games bought on one account can only be played when account is logged in

... and make sure that this account is the ONLY account to be set as Home console, or

game sharing will not work !

Ok so why does the xbox need someone(who bought a game) to login just so another person who didn’t buy the game to play it this wasn’t a issue on the play stations why is it a issue here

Its not an issue on playstation because youd have your playstation activated as the "primary system" under your main playstation account. Xboxs equivalent to that would be setting your "home xbox".

Youd have to set your xbox as the "home xbox" under the account where the purchases were made

https://support.xbox.com/en-US/help/hardware-network/console/my-home-xbox

Doing so will allow other accounts on the same system have access to play your purchased games without your account having to be signed in.

If your account has the game and gold, set the console he will be playing on as you account's home console. He can then log into his account on that console to play the games and you can be on your console, connected to the internet, and play.

Either account can log into any console and play, but can only be logged into one at a time.

I guess these were bought when I was logged off. And therefore not on my account

What do you mean you bought them while "logged off"?

All purchases you do on Microsoft Services have to be tied to an account. So it might be that you were logged in to a DIFFERENT account.

Since it's not possible to move purchases from one account to another, you will have to sign in with the other account that you used to purchase the game, and download that account to your Xbox console as well.

Then that account can see the games under "My Games", and if necessary, that account can set the console you're mostly playing on as that account's "Home Console", so your other account can play these games on that console as well.

On one console, the account which bought a game must be set as a home box account. At the same time, that account must be logged in another box. On the first box, all other accounts will be able to play any game that account owns, including subscriptions.
But I,m not sure that you can play the same game in the same time on both consoles. You can have only one home box and it can be changed 5 times per year.