Look through the images in the article and show me one huge, flat, unadorned surface. Building materials all go in and out of fashion - this is not about concrete.
What I love about brutalism is that the forms of the buildings are totally different to anything that came before them. Concrete freed architects - allowing them to build 'floating' buildings on thin stilts, huge overhangs and flying walkways and bridges. Now of course, more freedom is not always a good thing. I am not an advocate for every brutalist building - many are terrible, but there are some (like the ones in the article) that are gems, and should be preserved for the wonderful things they are.