I find architecture that slaps old forms onto new buildings to be...gross. There's a couple of skyscrapers just outside of Houston, for example, with fucking red shingles on it, like it's an adobe house in the desert or or something. So much architecture glues on a bunch of columns, ornamental lintels, fancy molding, etc. When placed on a structure that is huge, particularly one that is much taller than it is wide, they look ridiculous.
I think there are good buildings that were built in almost every era; but, some eras are less ambitious than others. Brutalism was, at least, ambitious. I think there's a reason so much scifi and futurist imaginings feature brutalist architecture. It is an architecture that screams "there are no limits to what we can build!" I think that's pretty cool.
It's all subjective, of course, and we all have our preferences. But, calling it "objectively wrong" seems hard to defend. It is only objectively wrong if it fails to function as a building for people to live or work in. If it leaks, if it falls down, if it is difficult to heat and cool, if it inaccessible to the people who need to use the building. Those are ways to measure architectural wrongness objectively. It's safe to say that some brutalist buildings failed to live up to their purpose, but that's true of many architectural projects. Having the style fall out of fashion, due to a reactionary response to the new and very different, and the buildings fall into disrepair because of it, is not really the fault of the architecture. Old buildings get renovated every 20-30 years, or they stop being relevant. This is true of even iconic buildings like the Empire State building.
Anyway, I quite like brutalist architecture; I don't mean I like it with no discrimination. I still just buildings on their own merit and being in the right style doesn't mean I'll like it, any more than me saying I really love punk rock means I would ever listen to Green Day or Bad Religion. But, there are brutalist buildings that I find beautiful. And, a lot of stuff that followed that I find horrible.