Just because a church is a member of the Southern Baptist Convention does not mean that they are bound by anything the Convention pronounces.
I believe that's one reason the split was made from the Catholics.
Trying to get Baptists within a church to agree on something is bad enough.
Jimmy Carter’s Southern Baptist church in Plains Georgia (where he is a Sunday school teacher) is a member of the Southern Baptist Convention. I think he used to be president of the United States but his beliefs are not those of the SBC entirely.