If Disney wanted to know how all guests felt about their vacation experience they wouldn't have ended the survey when you said you had visited other WDW related websites. I think they cherry pick for a certain type of responders. I've had the same experience so, I too answered no to the question on my most recent survey.No it was complete. I had gotten a message thanking me, but I can't remember the exact wording of it.
But I have usually sent an e-mail to guest services for both negative or positive experiences.