As the problem is largely irrelevant to computer hardware or software it is off topic on Super User.
The setting is only on the TV, is independent of the signal from a computer and is not controllable from a computer.
I do not believe there is a place for this question on Stack Exchange at this time.
Electronics is for electronics engineers, not general electronic devices.
Movies is, I thought, more about movie and TV programs, not electronic devices they are viewed on. I could be wrong though.
There was a proposal for "gadgets" which this might have fitted in, but it failed to make it out of beta I believe.
Guessing why a particular design decision is made (in any kind of device) is something only the people designing it can answer which makes it nearly impossible for anyone else to authoritatively answer. If it were on topic it would probably be opinion based and closed as a result.