Is he pro-tivoization, or is he not against it?

I heard him talk about GPLv3 someday, and what he said was that it was a mistake to call it "GPLv3", as if it was the evolution of GPLv2, because for him it should have been a totally different licence.

Which I find fair: there are different kinds of copyleft (like MPL vs GPL), it makes sense to say that GPLv2 is a different concept than GPLv3. Whereas I don't know if anyone should use GPLv1 because GPLv2 sounds like it fixed GPLv1 without changing its spirit.

GPLv2 was clearly intended to let you change the software on your devices. In some countries, GPLv2 already prohibits tivoization.

However, big tech found an exploit: In some countries, GPLv2 allows tivoization. This was not intended by the authors of the GPLv2. There was another exploit involving patent licenses, and a reverse exploit about license termination that allowed some developers to extort some users. They fixed these and made it the GPLv3. It's a bugfix release, not anything new. You only don't like it if you relied on the bugs.

Well, that's not really mutually exclusive with what I said. Those who called it GPLv3 consider it's a bugfix, those who decided to stay on GPLv2 consider it's a new licence.

He is against the "GPLv3 or later clause" because the FSF could change the license terms if it gets hijacked.

He is against the GPLv3 itself. He's ideologically opposed to converting the kernel to GPLv3, even if it was possible.