That was my point. Membership numbers cannot withstand much contact with the truth, therefore the change in policy.
I think it’s more about the LDS Church pushing to be more mainstream—to be accepted into the list of Christian churches. I think in the past they have had problems being viewed as “one of the gang” when it comes to community services and organizations. Knock-down drag-out arguments only exacerbate the gulf between them and mainstream Christianity (assuming for the sake of argument that such a thing exists).