Maybe it is making a difference for you because it's increasing blood flow to the muscles and getting them warm, much in the same way a knee sleeve works?
You could test the theory by doing a more thorough job of warming up to see if that creates similar results. Or jamming yourself into a full body Spanx suit for the duration of the lift??
The description of why it works definitely sounds like bullshit, but that doesn't mean there's not a granule of usefulness in the method.