It's not that simple.

In the email you have linked to, he does not support tivoization. He simply says that he finds the term offensive (which is really funny coming from him).

Torvalds has also publicly stated that he doesn't think that tivoization benefits users, but it's not his battle to fight. More info on that topic can be found in the linked YT (linked at the precise time he is answering the question about tivoization, but the whole video is about GPL v2 vs GPL v3).

YT video: https://youtu.be/PaKIZ7gJlRU?si=RK5ZHizoidgVA1xO&t=288

Because anti-tivoization doesn’t make sense in a software license.

Imagine you make a smart toaster, and you make it entirely out of open source software. You release all the changes you made too, complying fully with the spirit of open source. People could take your software, buy some parts and make their own OSS toasters, everything’s great.

But for safety reasons, since the software controls when the toaster pops, you decide to check at boot time that the software hasn’t been modified. You could take the engineering effort to split the software into parts so that only the “pop on this heat level” part is locked down, but maybe you’re lazy, so you just check the signature of the whole thing.

This would be a gpl3 tivoization violation even though the whole thing is open source. You did everything right on the software end, it just so happens that the hardware you made doesn’t support modifying the software. Why is that a violation of a software license?

This is what makes no sense to Linus, and TBH it makes no sense to me either. Would the toaster be a better product if you could change the software? Of course. But it seems to be an extreme overreach for the FSF to use their license (and that “or any later version” backdoor clause) to start pushing their views on the hardware world.

Which confirms the point actually. The hoops companies have to jump through are pretty good hoops.