How can this be accomplished?
Bingo! The source of the rot must be dealt with. But I don't know how. You'd think - hope - that the majority of the board is for traditional scouting values and wouldn't put up with the leftist members but expel them. But maybe it IS all about the money after all.
The best thing that could happen is for the board to overwhelmingly retain the policy and actually build on it. I'm not a big fan of witch hunts, but this is war - every scout organization in the country which allows and affirms homosexual scouts and leaders should have its charter immediately revoked.
It's way past time for stern organizational discipline.