The 4 or 5 times I have checked out FBO's to start my flight training at, I always wanted to speak directly to the chief pilot/instructor. I felt like they would be a much better resource that would help to give me a more complete picture of the atmosphere than a CFI who may only see things from their point of view. However, that's still no excuse for a CFI to be disrespectful and cocky to you. You think the guy would be extremely helpful and enthusiastic about answering your questions in anticipation of the fact that he could possibly get you as as a new student coming his way.
However in answering your question, I am well aware of what you are talking about. I've come across a few of these instructors myself who seem to have that "i'm above you" mentality and i've had conversations in a group setting with some of these guys along with observing conversations with some other folks and I noticed they often gave the "you're an idiot" glare.
I don't know how many other flight training options you have available to you out in the Denver area, but if you are adamant about finding out more about this place, I would set up a time to meet with the chief pilot or whoever runs the show and when addressing your concerns bring up the fact that the CFI you were talking to was a duche and that if you continue to get treated this way, you'll take your business elsewhere.