The place has long since been demolished; I remember it from personal experience as a shopping centre where all the shops had closed, and as a car park where nobody parked.
The depressing nature of a lot of brutalist architecture (especially that created by governments) is the uniformity, homogeneity and the mass-produced faux-utilitarian feeling it evokes, as if the inhabitants are all interchangeable peons with no individual spirit. It's a reminder of the depressing local conditions that lead to that architecture coming into being in the first place.
https://www.theguardian.com/housing-network/2016/jan/13/brut...
It's worth noting that Phil is not just wrong about brutalism but also wrong about these examples being (primarily) brutalist. Not generally using raw concrete, they would not be considered brutalist. The modern "box" has been largely discarded by contemporary institutional architects in favor of rough, pseudo-gabbled, uh, crap, as shown in the majority of these examples.
I'd say a bad brutalist building is like a rough bureaucratic dictate whereas present bad institutional architecture is like a bureaucratic dictate but rewritten with contemporary niceness guides - "this is a notice concerning your rights under the involuntary amputation act"
Boring? Yes. Cold and functional? Sure. Just not brutalist.
Brutalist architecture is often considered soulless, but soullessness (in and of itself) !== brutalism.
[0] https://res.cloudinary.com/schoolprison/10_wwfagw.jpg (which was a school)