Though disturbing (on a number of levels) I think the episode was pretty well done. It demonstrates what is necessary to break an individual's spirit, especially one as strong as Rick's. It's as much a reflection of human history, as anything to do with the show. Brutal dictators engage in this level of barbarism to show the lengths to which they will go, to subdue uprisings and to remain in power. The scene with Carl demonstrated another successful tactic used by some in power: Place the subject into an untenable situation, and then show a small level of benevolence by releasing them from the situation, once they demonstrate willingness to do the unthinkable at the ruler's behest.
It wasn't pretty, but it wasn't far off the mark.
As for Glenn taking the hit (well, several, but who's counting?), the two-fer was a bit of a surprise, but it didn't bother me. In all honesty, Daryl is the only one from the group to which I have any real remaining attachment. It's worth it to continue watching, just to see the rest of them killed off
.