Even though the Polynesian has started giving out wristbands I don't think they are on the same level as Stormalong Bay, which means that DVC members can still swim at the Polynesian and the real question is why give out wristbands if their pool is not 100% guests staying at the Polynesian.
Finally is it really elitist to say that during the busier times like right before the Magic Kingdom closes that they should only let guests staying at the Monorail Resorts only get on the Resort Monorail, so the offsite guests don't use it as a way of getting to the TTC. No one has said that the Resort Monorail should be for those guests from opening to closing, so there is nothing elitist about trying to control the crowds during the busier times.
See below for the nature of the "elitist" claims. (And there are some that are giving the exact tone and implications of what you are saying no one is saying. Discussion is more than just the raw words on the page. Keep reading my lower response before you respond though

).
So you are staying at the Poly and probably paying $350+ for a room. You are leaving MK and are rushing to catch the last resort monorail back to your hotel. But you can't get on because there is a huge line of off site guests who are in front of you going to the TTC, even though they are supposed to take the express line to get back to their cars. But you don't care if takes you another hour to get back to the Poly by boat, beacuse you are non elitist. When you get back to the Poly you have a change of heart, and decide to complain to Management that for $ 350+ a night you expect to be treated better than an off site guest. When the manager tells you that WDW is a non elitist resort and you shouldn't complain you gladly accept his reasoning, and have a magical night sleep in your deluxe resort hotel.
This right here is where the claims of elitism come in. Just because you're spending more, you expect more on an open (read, not restricted) system. You expect, just because you pay more, to have your own say on how said open system works. You expect, just because you pay more, to have exclusive rights to a transportation system. No other resort, or resort group, does this. If I stay at WL, should I demand that only people staying at WL or Ft Wilderness use the boats? Staying at POR and POFQ, should only those resort guests be able to use their boats to DtD? Staying at BC/YC/BWI should only their guests have use for those boats? (Yes, they go between Epcot and DHS, understood).
The answer to all is no. They are transportation options to be used by all, and as part of the WDW monorail system, the resort is the same. Which brings me to this point as well...
The MK resort guests are
not the only guests who pay for the resort monorail. I mean, sure, if you were you'd have a leg to stand on, but you aren't. You are subsidized by the other nearly 20 resorts. Your "zomg we're spending so much" room rates would skyrocket if you were the only ones paying for it. (Are you willing to spend $500-$2000 per night on a garden view just so you have an exclusive monorail? Would enough others feel the same to make it profitable?)
Now, of course, this is all going by the implication that the resort rail was only for resort guests at all times. Which we know is not the desire for most on this side of things... with that most, I agree to a point. So long as provisions for those who have actual business at the monorail resorts are able to use the preferred transportation to access said business, it makes sense and would likely work. However, this timeframe is already creeping. It was from MK close to Express close. Now it's creeping to "a little bit before" MK close to between express and resort close. Slowly increasing the exclusivity time will eventually encompass the entire time it is open.
And you know what? So long as those provisions are made, I'd have no problem with that either! Again, as long as those not staying at, but having some business at (including checking out the resort, viewing fireworks from the beaches, going to ADRs, shopping, hanging out with friends/family, using the marinas and other recreational activites, etc) the resorts, have the same access to said resort stations as those staying at them.