Note that you have changed your complaint from "OP didn't present any evidence" to that you "didn't find them convincing". (I note that you don't provide any evidence for that claim. Shocking! What, are we supposed to just take you at you word?)
But if that's the case, so what? His article aside, it's undeniable that A) some people like McMansions and that B) a lot of people don't. He also notes right up front, "These principles are for the classical or traditional architecture most residential homes are modeled after." He is trying to make clearer what's going on in case B.
Your liking the McMansions is only proof that you're in category A. Maybe you don't know much about architecture. Maybe you're not a big fan of classical architecture. Maybe you're a fan of something else entirely. It is not proof that he is wrong about what makes something good classical architecture, that his explanation of category-B reactions is useless.
> Anyway there is a long history of weird superstitions and made up rules in subjective arts like this.
Yes, thank god we work in technology, where there are never any fads, superstitions, or made up rules that people really believe and try to enforce inappropriately. </sarcasm>
That technology has a lot of fads, superstitions, and misapplied rules doesn't mean there is no objective reality, that all opinions are arbitrary, that educated taste is meaningless. The same is true of architecture. The same is true of most human activities. Just because a domain is too complicated to be reduced to a small, human-comprehensible set of "objective" axioms doesn't mean there's nothing smart or interesting there. And it certainly doesn't mean we have to be condescending about any attempt to increase clarity.