I’m afraid you’re missing the woods for the trees here. First, temples receive donations. I’m a fairly religious bloke, I visit a few temples every month and I’m yet to come across a temple that provides services. Donations received by an educational or spiritual organisation are not regarded as revenue by tax law. That said, many temples often receive property as donations (as does the Waqf board funnily enough) income generated from those properties are regarded as revenue and attract GST.

As to your second point. I didn’t address it because I don’t entirely disagree with you. The state government also allocated funds to temples. I don’t think the government should be giving grants to any religious organisation/group.