You were correct in your actions. You even offered to wait for a while, and the guy who obviously thinks it's his private range ignored you. I think if the range doesn't want you shooting rifle caliber handguns in the indoor facility they should make it clear in the beginning.
You tried to be polite, the other shooter was just being an obnoxious SOB!
Cheapshooter's rules of gun ownership #1: NEVER SELL OR TRADE ANYTHING!