To this point, even adding say another 1,000 DVC rooms, IMHO, won't have much impact on traffic flow. Considering that 50% will come by the Magical Greyhound, the remaining half will have a car. It's not like all 500 come through the gates all at once. I have no idea what the actual impact is in terms of additional traffic volume, but I can't imagine that it translates to more than 10 cars an hour. I'm not a traffic engineer, but my gut says that's not enough to justify a $10 million dollar elevated overpass.
I think either your initial hunch (class warfare) or my hunch (eliminating a dangerous intersection) would be the prevailing theory.