Here's some input from a sales-type, albeit computer software and not audio hardware. To start, remember that a salesman is going to be focused on closing the sale, not necessarily on "your listening enjoyment." His job is to move hardware and he's likely incented via commissions to do so. It's how he makes his living, so give him a little leeway. We all have to eat.
If he's a GOOD salesman he will remember that your needs and desires are key components in the overall equation. In real life not everyone is good. Many salesmen are too focused on their commissions and forget to consider what the customer wants. That's a management or policy issue and the owner should be interested in the feedback.
I've also read that some in the industry feel being snooty is a qualifier as it runs off all but the most serious buyers. For the lazy types interested in getting the highest commissions for the minimal amount of effort it may be a useful tool. Only the most "damn the torpedoes" buyer would put up with some of these guys, so the salesman does end up doing less work. In reality it's also a good way to lose business as it also turns off the uninitiated and discourages less assertive individuals. They either buy somewhere else of not at all. That is bad for us all. Regardless of what he's selling, a salesman should spend at least a little time educating the market and playing emissary. If all of them did the market would increase and we would all gain from it, manufacturers, retailers and enthusiasts, too.
Also, don't walk into any retail shop and expect to find the highest levels of professionalism, smoothest sales techniques, etc. The guys that have mastered those are doing it where they make the most money. That probably isn't in audio (much speculation on my part). I do deserve, expect and even sometimes demand, courtesy and respect. I AM the customer, dammit! Solutions? Consider speaking with the owner or hiring manager, but don't be surprise if you may get more of the same. People tend to hire others like themselves. You can also be assertive with the salesman. Politely put take him to task. Point out that he is losing you a a potential customer by his actions. The key here is POLITELY. If done right he will respond in a positive way. The idea is to command his respect, not embarrass him or make a scene. The only other option is vote with your feet. If you do, be sure someone knows. It adds emphasis.