Sure, when you’re making two-grand-a-month payments or whatever, what are you gonna do, walk around admitting you’re driving a piece of crap?
Same could be said for any luxury car but the Model S blows them all out of the water.
Some terms for that feeling are "buyer's remorse", "post-purchase dissonance", and "cognitive dissonance". If you want to get globab, you can go with "Buyer's Stockholm Syndrome".
IOW, chatting up how great some expensive toy is reassures one's self that you didn't get taken, and trying to put a shine on crap by giving glowing reports is a way to attempt to massage that niggling sense of doubt.
I have no doubt you're right on the money.
However, there is that highly valued segment called "Early Adopters", and Tesla's survey might just have a self-selecting customer base custom-made for them.
Perhaps if there are any rental companies using the vehicle, people using the car for days or a couple of weeks with no ego at stake might have a more realistic view of it.
Way back, a room mate was picked by Avis to drive the brand new Ford Taurus for a week for his comments. He had a VW Golf and a Lotus at the time.