If we listened to every piece of advice of this nature, we'd sit and do nothing...then guess what....yep, they tell us that was bad too
I've seen the same sort of arguments put forward concerning yoga postures, admittedly some are bad (or not so great for you, depending) but the ones where they say they are detrimental and want to prove the point on, they will go to extreme lengths and use examples of "incorrect and unsafe" use/movement which is not the same as correct and safe movement...pretty much where Scooby is going concerning the squats, as Aurik highlighted, people build up to those weightloads which then ensures some degree of safety; everyone knows that an injury can occur at any time even with near perfect form.