Why did this man treat me like this?

I have to see a psychiatrist for a review. This man rang up and told me of my appointment. He spoke to me very slowly and as if I was a little kid. He went to great lengths to make sure I knew it was with a psychiatrist and kept making reference that I had to see a psyhciatrist. I said thank you. He laughed at me hysterically as if he was the one who needed treatment. There is nothing really wrong with me, it is just a review. Why did he treat me like this?