I don't know if you know this, but Batman isn't exactly a happy guy.
New city, same shade of gray... but not for a lack of trying.
Here's an image of Batman looking at a dog. There you go.
2016 takes something else from us, and this time it's Chew.
The gift of Clayface, TAKE IT IN MAAAAAAAAAAN. (reference!)
Maybe he is intentially ignorant
His heart to heart with Batman at the end of Knight (he calls him Bruce) and they way he talks to batgirl in the DLC leads me to believe in the Arkhamverse he knows who they all are and is intentionally ignorant.