I think the author is overstating his case, obviously on purpose. ("WRONG" -- we're clearly writing for effect here.)
That notwithstanding, there's definitely a "there" there. This mind-muscle stuff is some powerful ish, especially (a) at the end of failure sets, (b) to protect joints, (c) recovering from injuries.
(a) I've been able to pump out 1-2 additional reps when I thought I was fried, just by visualizing those specific muscles going bam! and then feeling that connection.
(b) Especially with heavy lifts like squats and DL's, there's always that harmful natural tendency to think of the lift as being a "joint" movement. (As another example of the same focus on joints -- when you do high-knees in football drills, everyone says "Knees up". And they're called high knees. Obviously the knee isn't even that relevant -- they are hip flexor contractions -- but people focus on the joints because they're the joints.) By focusing on the muscle exerting the movement, you can actually take some of the stress off the joint, because you aren't thinking about the joint anymore.
(c) I had reconstructive chest surgery, and had to build my left front delt and pec back up, excruciatingly, one muscle head at a time. Especially when I was training the weaker heads, it took an intense mind-to-muscle connection to make them work hard (otherwise the disproportionately strong heads would have shouldered the bulk of the work).
This is good stuff.