English is my native language and I still don't understand the title even after you explained it, but the article was interesting anyway. Maybe "Humans who are not concentrating may as well be dumb humans?"

Humans who are concentrating are acting with general intelligence. Humans who are not concentrating are acting with lesser kinds of intelligence. The title is pointing out that human intelligence is not always the 'general intelligence' that is supposedly unique to humans. It is grammatically correct, but you have to understand that "general intelligence" is a term of art.