A couple of updates: I tried just responding "None" to the "Answer these questions to find a new survey" pages (although some required some sort of answer). The supply of surveys seemed to slow down and then I got an e-mail from e-Rewards on "How to Unlock More Surveys". The answer: provide information on those pages that don't give you any points. Bah. Have started answering them and I'm getting a few more.

Don't bother with anything on vaccines. Twice I took surveys on that subject, provided a good amount of thoughtful input to their questions (my attitudes, what persuades me/dissuades me in deciding which to get) and then got kicked out.

E-Rewards really needs a "Report this Survey" button when you get kicked out with pity points. Even if they didn't check every complaint they could look for the surveys that get a lot of them.