Unfortunately, though, I think if your strategy is "hope people adjust their behavior on your own" then your sales pitch isn't going to be effective.
So if we want to change the status quo, how do we make it over that preaching-to-the-choir hump? (This sounds rhetorical, but it's more cynical/frustrated, actually - I don't have the answer.)
Stop saying "You disagree? You must be an idiot." to start. It's not always so explicit, of course, but it's pretty easy for a solid dose of scorn to slip into an argument that the true believers won't notice.
Another exercise is to try presenting (to yourself) the very best argument for the opposing side that you can. Now compare, is this the argument that you are refuting?
So if we want to change the status quo, how do we make it over that preaching-to-the-choir hump? (This sounds rhetorical, but it's more cynical/frustrated, actually - I don't have the answer.)