Then what about Romanesque architecture, with hand railing that are far too large to be used as handrails, its thick walls and tiny windows? Victorian architecture with it's total lack of symmetry and wide variety of architectural features with no purpose? How many Victorian era houses are there in the US with doors to nowhere, again?
The scale of railway stations and churches are intended to make humans feel small. The scale of the main, brutalist style building at my city's university is much better in proportion to humans than the giant cavern that is the inside of Grand Central Station. Classic architecture has doors that are 30 feet high! To what exactly is that in proportion? A brutalist building covered in plants with all of its hidden features and corners, shapes and textures, landscaping and ponds, is actually a lot of fun to explore. Moreso than a palace like Versaille where the wide, symmetrical facade lays everything out in front of you, leaving little mystery. They're very natural, that is "like nature", while classicism, with its strict rules regarding lines and proportion, is unnatural and man-made.
A lot of classical architecture is just taking a symmetrical box and sticking fancy statues and carvings all over it.
No city should be built uniformly in one architectural style. Modernist buildings in historic cores in Europe add a lot of excitement to those neighbourhoods. The presence of a modern building surrounded by classic ones only emphasizes its architecture more. That contrast is important.
Keep in mind that most of the criticisms you have of brutalist architecture with regard to its scale, proportion, detail, and suitability for human occupation were made 50 years ago against Victorian era architecture. These same arguments about architecture led to the architecture you're arguing against now!
(Just want to note that I don't dislike Grand Central or Versailles at all, they're both magnificent examples of their architectural styles, I was simply using them as examples in the argument.)