While he does mention a sentence on it, I think in his preachiness he does a poor job of clarifying that he's arguing against excessive arch and specifically excessively arching your lower back. His point is that its bad for your lower back from a longevity standpoint and because of the restricted ROM it can interfere with progress just as much as benching off of a 3 board all the time would hamper your gains.
Many of the ways he reasons arching your lower back is bad are actually highly flawed, however. Saying that because it hurts to do that if you have a herniated disc means that arching your back is bad is violating an alphabetical assortment of fallacies. I think the fact that your spine deviates from its neutral position is the more highly effective argument, which I think he mentions briefly when saying how you wont be tackling a player with an arched back like that (or you damn well shouldn't!).
I think the points about building a bench with conservative technique are on point, though. Bear in mind the article was probably written for your average/above average gym rats, not necessarily for coaches or elite athletes, who find this information redundant and should already know it. But one thing I might disagree with is that for the powerlifter, your main movement should mimick what you do exactly in competition; just as football players don't practice playing football with a blindfold, powerlifters shouldn't only practice a close grip bench as a main movement - they need to practice and hone in their regular bench groove. For accessory work, yeah, that's when you can throw in other movements with increased ROM to help build the bench.
This is a decent piece that's helpful in keeping lifters honest about what they're doing in the gym. Without these perspectives, a person could be cheating themselves out of good gains.