Question 1: when I had GDM I was teetering on the brink of needing insulin. I told the Diabetes Nurse Educator and the endocrinologist that I was really keen to manage it with diet because using insulin immediately put me in the high risk category. They were both really perplexed and basically said "why???" My research backed that up. It seems that regardless of how it is controlled it is good control which matters. I wonder if your doc is getting confused with pre-existing Type I diabetes which does have increased risks associated with it.
Question 2: actually there is all manner of research to show that routine CTG does not improve outcomes.
I'm sorry he is being a pain.