A critic, ou analyst, does not need to be a good practitioner to provide the public with interesting insights.

The "you can't cook/compose/etc, how dare you criticize the food/music/etc" line is rather crass.

This criticism doesn't seem like it fits for the actual content of the article. I read through it and didn't see much appeal to authority going on here, it's arguments mixed with opinion and justification/examples.

It wasn't really about this article in particular, I was wondering if I've just missed a reason why and the answer seems to be no.

That never stopped John C. Davorak.

JLG is known and was at Apple. That makes him incredibly qualified. Somehow.

I don’t know. He doesn’t seem worse than many other random columnists.

Dvorak was always just a troll, Gassée tries to be some kind of visionary

This is not uncommon amongst executives. It’s often described as “failing forward”.