Nearly every comment is missing his take given the title here.

He's not saying everything should be open source.

He's saying that the right to have an open source version of anything is what we should be absolutists about.

So not that every OS, or encryption, or AI model should be open - but that people should fight and stand up for the right to have access to open OSes, encryption, or AI models if produced.

Windows can exist, but shouldn't be able to prevent Linux from existing basically.

That's the absolutism. He hasn't suddenly turned into Stallman.