So, I looked a bit closer at this image, and found something...
On the very right, where the yellow kanji are on the "sign" of sorts, the kanji is "教育的指導" which means "educational leadership" or "educational guidance"
I feel this fits even more with the emancipation theme. What if one of the dungeons is a distorted or warped version of Shujin High School? Think about it. What castle with knights and all has a sign that says "educational guidance"? The kanji for "shujin" in Shujin High School is are "秀尽" The first kanji (秀
can mean "excel" or "preemptiveness", while the second (尽
can mean "last day" "end" and "exhaust" amongst other similar words. We already know the name is a play on words while still having a specific meaning behind it, which I believe was explained in an interview with Hashino in February.
Those who don't excel or are not already prepared (preemptiveness) need educational guidance, and this is the distorted version of the school, which is formed (I don't mean literally formed by the people, but by their thoughts) by those who were held down due to not being able to excel, and exhausted their efforts. I know the theory does sound weird, but it does make sense. Especially with Hashino saying that he wants this game to have dungeons a phantom thief would infiltrate. Something about this place must be important to the story, or at least important during the point of the game where you infiltrate and explore it. This place even has a flag with an emblem, so there must be some group behind this place or something of some sort.
Maybe the dungeons are all formed by those who are held down or things that hold people down; their thoughts making the occurrence happen. And, the main cast are the only ones who can stop it and "free" everyone by being breaking out of the societal norms. It feels like Persona 5 is going in that direction.
I'm not saying the people literally form it. I mean the things that hold them down themselves may form these dungeons, and may have caused the occurrence at the start of the game. This is just a theory, after all. However, I still find this very interesting.