Not to mention that it's questionable whether the average Republican gives more than the average Democrat, or if it is just a case of a small population of extremely wealthy individuals donating large amounts for reasons of tax benefits (in addition to the political motivations you mentioned).

Then there's also this from one of the authors of the study: 'It also wasn’t obvious “whether donors were being purely generous or whether they would also benefit from their donation. This relationship is called consumption philanthropy, in which people give to a religious organization or a school from which they will derive a benefit in the form of, say, a better religious education program or a new gymnasium.” Giving to a food bank or a homeless shelter has a very different outcome than does giving to a private school.' (https://nonprofitquarterly.org/republicans-give-more-to-charity-than-democrats-but-theres-a-bigger-story-here/)

"Without context" is one of the favorite argument methods of conservatives. It's not that they disagree about the context. They don't understand the concept of context nor its relevance.