The BOLD response (oxygen-neuronal activity coupling) has been pretty much accepted in neuroscience. There have been criticisms about it (non-neuronal contributions, mysteries of negative responses/correlations) but in general it is pretty much accepted.

The measurement of the BOLD response is well-accepted, but the interpretation of it with respect to cognition is still basically mostly unclear. Most papers assuming BOLD response uniformly can be interpreted as "activation" are quite dubious.

Yes, I stupidly read the headline and said "no duh" but they are making a point about our understanding of brain activity. I was thinking about the part of the signal that is reliably filtered out, they are talking about something else. Sorry, I was wrong.