User blog comment:XGlass Reflection/Ch. 50 Review~ Lesbian love!/@comment-13234254-20131008163938/@comment-179280-20131009011532

@ Of course they are mass murderers due to how they were raised and ordered to attack humanity and erradicate it, but you cannot deny they DO feel remorse about their actions. In Chapter 42 you can see how Reiner confesses he had no idea what they were doing, because they were sent to infiltrate the human military (presumably being convinced that humans were monsters and that they deserve death), but he declares that he didn't know how they really were (implying that he actually started to care for and trust people he was taught of as "monsters"). This is what triggers his sanity slippage. Bertholdt also shows this in Chapter 48, when he confesses he actually enjoyed being surrounded by people he started considering as friends, but knew they would hate him if they knew who he really was. Annie also goes through this in Episode 13, when she apologizes to corpses of dead fellow trainees.

What I'm saying is that even though all of this doesn't justify their actions, Isayama is actually trying to convey that all characters have reasons to do what they consider "good". Hell, you even have our hero killing two grown men when he was a child. Is this justified? It depends. It's the same for every Titan Shifter if you think of it.