I never studied architecture, but one thing I’ve noticed about Brutalist buildings is that the exterior is very rough in many cases. Makes you not want to touch them.
I don’t go around touching buildings but something about most other styles does compel me to want to reach out and have a tactile sensation of the construction. Brutalist buildings seem to have to be endured rather than enjoyed.
I have been in that building many times and veer between an affection for it and wanting it painted or even demolished. Although it looks like a bunker, the building is unusually spacious inside, with high ceilings and large rooms. The architect got that right at least, which is why it has endured.