There are a few issues here.
It is quite possible for an organisation like the SA to have an all inclusive ideology but that doesn't mean that all of their members agree with it and there will inevitably be some whose actions are incompatible with that ideology. It is surely therefore incumbent on the SA to weed out those members who clearly don't abide by it's doctrine, however, as a fiercely Christian organisation, it's difficult to see an all inclusive ideology getting through to all of the grass roots if some, maybe many, fundamentally disagree with it as they believe that all real rules are not set by the organisation but by a much, much higher force.
As others have pointed out, the SA do sterling work for the homeless and my wife has occasionally volunteered to help them feed the homeless on Xmas day so are they still worthy of financial support for the greater good that they do? It would be interesting to know what proportion of the people who need their help are LGBT+ and what proportion of those have faced the reported rejection?
