This article is purely subjective. I'm sure there are some academics that could explain ways to objectively score usability but this article is purely subjective.

No. It's completely subjective.

The whole "AI slop" noise is, at its core, human slop. It is people applying a hopefully pejorative label, trying to appeal to other slop aficionados that like whatever the current trendy slur is, in an objectively undefinable way.

In this case this guy likes the way Qt apps, they think it looks better, but it isn't a big trick they are revealing: They made it conform to the style they like, but this doesn't translate to anyone else in any measurable way. I think web apps looking like Qt apps feel like the late 90s and it's just weird, but my taste also is entirely subjective and mine alone.