Everyone has a right to decide what they find disgusting dearie.
Sure.
But you are being severely hypocritcal if your supposed to "Care for the poor and downtrodden" or in this case, the SA is supposed to help the homeless and those with less, unless you're gay or lesbian or trans or part of just a select group of people.
Personally I don't see the SA as something to bother with. I'd donate to the red cross or some other organization that serves everyone, than them. Knowing that the SA are religious based, to be honest I'm not surprised by their exclusiveness when it comes to helping those who need help. I also think it's pointless to bother to try and change them. Let them be exclusive; give to other charities instead.