Yes! Thank you, I get annoyed when people think there is one definition of good design/art/beauty ...it's a thinly veiled display of narcissism. It's like trying to tell someone what kind of food they like, or who they find attractive- there are trends, and sometimes it seems like there are rules, but nothing is ever 100% universal as far as I can tell.

The article is discussing "simplicity" as one aspect of design. While I agree different designs can really only be viewed subjectively there are some aspects of simplicity that can be judged objectively.

It's pretty clear that the superiority metric is going on what the site's intention is: conversion.

So while you're right it's not superior in every metric, it's superior in the only metric that the people creating the sites care about.