Yeah, it is proof that Linus acknowledged it
The receipts show LTT plagerized, Linus promised to fix it but didn't. Steve thanked him expecting that Linus would do what he promised but then Linus did nothing.
3 years later after GN publicized the unethical behavior, Linus then, and only then fixed it.
the writers to not forget citations again and put up a pinned comment, which he did,
But he didn't. He promised to but never did until 3 years later. That's why Steve called him out.