The Ghost of RubangB said:
I say good riddance. People like helping people. If Catholic gay-hating charities disappear, non-Catholic Queer-friendly charities will replace them. I think Bill Gates and Warren Buffet have donated billions each to charity, and they're not Catholic, and they're definitely not going to stop helping people if we pass a law they don't like.

While I don’t know about Catholics in particular, I do know that charities that fall in-line with the values of Evangelical Christians and Mormons tend to have no difficulty fundraising or finding volunteers; while charities that are against the values of these religious groups have difficulty surviving without the aid of the government. I’m not religious, but I do know that these (often criticized) religions tend to volunteer and give to charity at disproportionate levels; and if a "Charity Strike" was started by the Catholic Church and followed by other denominations it is likely that charitable organizations would grind to a hault.

Realistically, I don't think this would happen because of the nature of people who volunteer, but I think you need to consider that many of the devoutly religious individuals see a greater need to volunteer; and as a result may be out working for multiple charities three or four nights a week, and these people are not easy to replace.