Here are the facts laid out since everyone seems to be confusing them or just flat out pretending they don't exist.
1) Everyone has known that the iMac Pro is essentially non-upgradeable. It was intended to be this way. It was no secret, and anyone buying a $5K machine knew this ahead of time.
2) Linus broke it when he tore it open. Not just the screen, but the Logic Board (which includes the GPU) and the PSU. This means there are possibly other components that may need repair that are smaller, but these are the 3 "big" ones.
3) Apple doesn't sell parts to individual consumers. Common knowledge.
4) Apple reserves the right to refuse service to machines that were broken due to "misuse" (in this case, pulling everything apart and trying to piece it back together).
5) Apple is capable of repairing the computer.
6) The parts are available for the computer.
7) None of the businesses he spoke to want to fix it because it is a waste of their time and money, and could make them liable for future repairs.
8) Linus is making money off of BOTH of these videos, and it stands to reason that his outrage manufactured for profit.
9) The computer is a total loss. That means the cost to repair or replace the damaged components is near or at the cost to replace for Apple. Replacement with a refub was not an option given that he was not under warranty.
10) New warranty laws from the FCC are not relevant because all of this occurred BEFORE those changes happened.
I think I covered everything here. He knew the risk, he took it, and he ended up with a brick because of it. If you buy a high demand / low supply niche product for the sole purpose of tearing it apart, you know exactly what you're getting into. If you don't know, it's likely because money isn't an issue to you, at least not a big enough issue that risking $5,000 seems unreasonable.
Don't get played. Him being a "YouTube" star is completely relevant to his behavior. The fact that he gives you a brief (and inaccurate) synopsis at the beginning of the video, and then IMMEDIATELY goes into his Sponsorship speaks volumes. It's a work.