Here is your explanation in simple terms. The legal process is a lot like making sausage. It may work out in the end, but you do not want to watch the process of how we got there haha.
I believe the answer to your question is that his decision is not as cut and dry as we think it is. Both parties submitted replies that were many pages long, with many different arguments, and references lots of other case law. I would imagine it takes time to digest everything and how to correctly apply the law based on the arguments made by both parties.