User blog comment:Yxz2014/Has anyone noticed this before?/@comment-25358468-20140820223943

Pretty sure the Wall Titans were protecting humans against Titans, there isn't any other enemy really, and I doubt humans would have had time to fight each other with no protection of the Walls guarding them.

But yeah really interesting images and I'm pretty sure since Isayama and Wada talked about how the series was going every two months, they wanted to implement plenty of spoilers and symbolism (B.R.A and Ymir around the Wall, the "other ending") and such.