Charitable activity provides a lot of political cover for really shitty religiously motivated behavior. For example, giving money to the Salvation Army is probably a net-negative effect on the world.
It funds anti-homosexual political activity, attaches onerous religious proselytization to their poverty outreach, subsidizes in-your-face guilt-tripping bell ringers, crowds out other anti-poverty efforts, and reduces the charitable effort that donators bring to more worthwhile causes.
It's not literally the worst charity - that probably belongs to Susan G. Komen - but it is pretty terrible.
What?