Well your profile icon matches your intelligence.
HDMI-CEC is what allows you to use your TV REMOTE to function on your DEVICE, it's an old feature from 2006 or earlier that makes things much simpler and works almost universally on ALL DEVICES.
Easy peasy.
I get it you're a troll, great posting.
When HDMI-CEC is working correctly it should automatically go to the input of the device you just activated. You should file a bug as this is a HDMI-CEC issue.
If you have your device set to NOT turn off everything when you turn it off, the TV you have on SHOULD return to the previous HDMI port that was in use before turning on said device.
Here's a usage case, I turn on my PS4 Pro(has perfectly functional HDMI-CEC) the TV is off, my AVR is off, it turns on my TV and my AVR and all of those things instantly go to the correct port, regardless of what was previously used(usually port 3 for my cable box) when I turn off my PS4 Pro the TV goes back to HDMI Port 3.