This thread sounds the whining going on over at one of the other forums.
It's the same whining that's going on in about six other threads on this forum alone.
If you see it happening I would suggest putting the sales rep in their place or asking to speak with their manager.
If you're going in to get a new phone for yourself be firm with the sales rep, tell them what you want and shut them down if they try and make another recommendation. I got my Lumia 800 from Carphone Warehouse in Northern Ireland, walked in, told him what I wanted, played with the phone while the guy did the paper work, checked and signed the agreement and walked out.
I don't know if you have stores like that in America? They're a mobile phone retailer but they sell on behalf of the networks and often have a better range of handsets/deals than the network branded stores. Largely because they can sell unlocked phones with a carrier subsidy. In my experience, stores like that aren't as biased about what you buy, as long as it's expensive.
Sales reps are supposed to facilitate the customer by listening to their needs and making a recommendation. Not forcing their views/bias on the customer. The problem of course is that generally the reps are fairly tech minded and are as much fans of the various platforms as we or the android/iphone fanbois are. I can imagine it would be difficult not to try and sway people towards the OS you have a personal preference for.