Why should my opinion of how credible he is as a writer about Apple be affected by people who work at Apple not liking him?

The comment asks what’s the grift? How is he irrelevant?

You ignore the questions and respond with ad hominem attacks.

Obviously, you’ve got a beef with Gruber. That’s fine. But you’re acquitting yourself well here (and make us suspect that whatever happened between you and Gruber, you might have had a significant hand in it).