That seems to be the majority opinion, at least in my experience, but I've always really liked it. Maybe because it reminds me of so many science fiction settings. I do think blending the buildings with plants goes a long way to making them look more hospitable.
For me the design always comes second, their sheer scale is what makes them amazing. Seeing them from the distance, thinking they're nearby, but then you just keep approaching and approaching and they keep getting bigger.
What this slideshow does perfectly is picture them from a POV perspective, nowadays you mostly see drone shots.
I completely agree with this. Have you ever noticed how very tall but narrow buildings (i.e. skyscrapers) are never as physically imposing as bulky, monolithic buildings that are as nearly as wide as they are tall?
The problem with brutalism is that it is literally inhuman - it creates an environment in which humans do not fit.
So in theory, nature could help, because humans feel that they fit in natural environments. But in practice, at least in the photos in the article, it doesn't work, because the nature doesn't look like it belongs there either. It looks either like weeds growing through cracks, or "tacked on", ineffectively trying to make you ignore the ugliness.