Because it is a different world! That’s why! The LGBT is an idea that happened in this world when humans had enough time off from surviving to think about that stuff, but the dragons, while being at the top of the food chain, and having it pretty good, they are different from humans, and they still have to be concerned with the day to day act of survival, they still have to hunt for food, etc. So, they son have enough time of surviving to worry about sexuality and gay, lesbian, LGBT, and all that crap. So, they don’t need LGBT ships!