I cannot agree with this statement, in fact IMO it's just plain wrong.
First, if the pistol were dropped on the REAR of the slide the bottom part of the trigger would be carried towards the REAR of the pistol due to simple MOMENTUM.
Second, I have rather narrow fingers and if I take a "High" grip on a S&W M&P 9mm I can sometimes find the trigger is locked because my finger is too high on the trigger to swing the bottom half far enough to disengage the trigger safety. Because of this my carry choice has been either a Sig Sauer with no trigger safety at all or a Ruger with the classic split style Trigger Safety copied from Glock. BTW, I have never understood why Glock as allowed these copies and suspect this type of trigger safety may actually have been patented way before Glock ever existed.
Third, S&W advertising literature describes this as a TRIGGER SAFETY.