Is there really no way to explain this simply or slowly enough for you Screeb?
It is google that controls where the videos are served from (TCLs google cache, or any of their points of presence).
It is google that controls how much bandwidth is available from any of these locations.
If TCL is able to provide good speeds to other international destinations (as you have stated) how is it that you fail to comprehend that it is google alone that influence your experience with youtube?
TCL is possibly guilty of taking too long to realise that bending to googles will was inevitable. Through controlling the highest value content google can force any eyeball network to do whatever they desire.
All they needed was you, Screeb, and rest of the technically ignorant masses to do their bidding.
Note: I mean 'technically ignorant' not as an insult but as a description of people lacking in knowledge of the applicable technology.