Brutalism is a style, not a term of abuse. It does often refer to high modernist 1960s and 1970s buildings which are expensive to operate, having been constructed before environmental friendliness was on the agenda. Some people don't like the rectilinear boxes and raw concrete, but that's not why the term brutalism is applied to a particular subset of the buildings of that period: it was the popular name of an aesthetic movement, for better or worse. The architects in question were influenced by the Japanese aesthetic of wabi sabi, as well as the notorious (but admittedly brilliant) Le Corbusier.