This is not hard to understand. The TV may be tied to one iCloud account out of necessity, but it is a shared device. It is preferable that this device only show Photos that are deliberately shared. It is welcome that it has that level of security, so that not every single photo you snap ends up on the TV.
Photos that you Share are very likely akin to photos that you "wouldn't mind seeing pop up on the TV" for anyone that happens to browse your photos or watch your screen saver, etc.