Wow, that's a really limited scope.... not bad info though.
Frantz and Inzer bade the first early shirts around the same time. Frantz actually sued Inzer over it but the judge found that there wasn't enough to show who had done it first ( let alone patented it).
The part on working the shirts is off too..... a poly and denim both work by stretching the material, but obviously there's not as much stretch in denim. The article mentions wearing denim looser - which is true - but you also work them differently. Poly is worked with your chest up and head back - although some guys do a little roll, which is how you'd work a denim. Denim is worked through tucking the elbows in and rolling the shoulders slightly ( lifting your head).
It should be noted that the different types of poly are worked differently too. A stiffer poly like a Katana or Overkill-Black is worked in more of a denim groove - more elbow tuck and a lower touch. The Rage-X is similar but slightly less supportive, so it can be worn lower ( more later)...... a stretchier poly like an SDP is worn a lot lower and lets you bench with your elbows out more - not as much tuck is necessary and you can touch higher. The Overkill-Red is somewhere in between and can be worked either way.
The biggest missing link is the adjustment. Shirts are worn pulled all the way up in the arm pit with the collar all the way up - when you want to touch easily. Pulling the collar down lower makes it harder to make a weight touch, but adds more support. Wearing the sleeves lower does the same on a much larger scale.
Going along with that adjustability is a HUGE missing link - how much bench shirt you can work ( by brand, ply, fit, and how you wear it) largely depends on you having the strength (and guts) to work it..... this goes the same for squat and deadlift gear, but there's relatively little easy carryover. Put most guys in loose gear and they'll hit depth and touch in a workout or two, but it takes a lot to work to learn to handle the gear and build up the strength to support it.