I don't remember him calling Linus a terrorist, though there were others that associated anything with a copyleft licence to be the loony left (or the commie left).
He certainly referred to both him and Linux as cancers though, that I do remember. He later changed his mind on that, and IIRC may even have publicly apologised for those statements.
He said Linux is a cancer, which was a stupid thing to say, but not the same as calling Linus a cancer. I say plenty of bad things about software that I would not say about the people who create it. I think Next.js is awful to use but that doesn't mean I think everyone at Vercel is an awful person, for example.
He may not have used the word cancer with respect to individuals, I can't find any such reference in a quick search, but he certainly had harsh words to say about proponents of Linux/OSS/similar.
He certainly referred to both him and Linux as cancers though, that I do remember. He later changed his mind on that, and IIRC may even have publicly apologised for those statements.