For this to be relevant to a claim that Glocks are problematic from a safety point, it has to be viewed in light of other service pistol candidates, otherwise this is just a problem with guns in general.
So, presumably the author is making the point that because officers instinctively put their fingers on the triggers and that's a problem with Glocks, if they were using other guns, based on a different safety system philosophy, that would prevent this from being a problem in normal use.
How, exactly, would that work? For example, in a gun with a manual safety, is the author claiming that these officers will leave their safeties engaged (per training) so that they can "safely" put their fingers on the triggers when they don't intend to fire? The problem with this kind of argument is that it says that we can solve a training problem by changing to a different operating system and assuming that there won't be any training problems with that new operating system.