That option is available when a receiver is part of the setup, and when HDMI-CEC with power functions is offered and active on the TV and receiver. Many fully featured modern receivers have CEC always-on. Many TVs have a separate setting for that, and they may have their own trade name for CEC.
Did you change something to the setup? Is the receiver in between the Apple TV box and the TV? Is CEC turned on (activated) on those other devices? Receivers connected by optical cable cannot get CEC signals through that wire. Receivers connected wirelessly cannot get CEC signals. CEC requires the HDMI connection.
Try resetting the HDMI connection by unplugging both sides of each HDMI cable, then re-connect. Restarting (real restart; not standby-wake) all devices involved would have the same effect.