I would recommend studying the history of the Catholic Church and its current stances from the pro side as well as anti. Rodney Stark’s book The Victory of Reason is a good resource for historical issues from the pro side. In current issues you could look at how the Catholic Church has stood up for human rights, workers rights, and democracy in the third world, particularly Latin America. After doing so I’d imagine you’d feel quite all right about giving the Church money.
Which human rights precisely? The rights of women, homosexuals, people who want to have safe access to contraceptives and abortions, people who are abused by members of the priesthood? Those human rights?
Of course one of the things the Church has done is preserving these great works of art.
Art is eternal. The policies and practices of the Church are not.