"I see, so, the Mad Hatter somehow inserted all of that into Batman's mind? " - ExplorerDS6789
The Mad Hatter only provided the means for Bruce to imagine his perfect dream world. Everything in it was a product of Bruce's imagination.
"It's a plot hole, but apparently the Mad Hatter was so consumed with just keeping Batman out of his life, that he never bothered to unmask him."
I know. The villains are always too cocky to unmask him. But if they found out he was Bruce Wayne, what would they do?
That was illustrated in another dream episode,
Over the Edge
: "If the Bat's on a spree, Wayne must pay the fee!"
http://www.tv.com/batman-gotham-knights/over-the-edge/episode/115354/summary.html

I see, so, the Mad Hatter somehow inserted all of that into Batman's mind?
"It's a plot hole, but apparently the Mad Hatter was so consumed with just keeping Batman out of his life, that he never bothered to unmask him."
I know. The villains are always too cocky to unmask him. But if they found out he was Bruce Wayne, what would they do?

Did the Mad Hatter know Batman's true identity? No, he didn't.
It's a plot hole, but apparently the Mad Hatter was so consumed with just keeping Batman out of his life, that he never bothered to unmask him.
http://imdb.com/board/10519611/quotes
Even though the Mad Hatter appears in Bruce's dream, that wasn't the real Mad Hatter, it was just Bruce's imagination. The real Mad Hatter never learned that Bruce was Batman.