There’s a lot to unpack in the quoted passage, but it is not an ad hominem attack. That you think it is, and then turn around to make an ad hominem argument of your own explains your misinterpretation.
I think this clause makes it literally hard to parse the argument. That’s because of who he is, sure, but that’s not an ad hominem attack on it.
The peanut butter comment was snarky, I’ll admit that! The point is that it’d be a remarkable achievement if somehow he hasn’t lost touch with a huge portion of most people’s everyday reality.
