Okay, article is jibberish.
Nothing is “bulletproof.” Something may be bullet resistant, but, it’s not “bulletproof.” Find a big enough projectile and the force behind it enough to penetrate and it will do its thing. Physics are a bitch.
Good range and a .308 (or larger) has messed up a lot of people’s day regardless of the latest fashionable protection gear.
"Oh geez, we're SO sorry. We thought you said you wanted pullet-proof jackets."