religious websites are a greater security risk than porn destinations.

[Angrboda]

I didn't read too deeply, as I was continually getting popups warning me about an invalid cert (thanks), but seeing it appeared that the different sites compromised ranged from 10-20%, a rather small spread, I don't think one can infer too much from it. This is likely simply a reflection of the well known fact that compromised sites are made up almost exclusively of non-porn, non-warez sites. As a result, it's unremarkable that one of the categories of legitimate websites comes out on top. A more interesting question would be why. I suspect religious websites may have three factors which single them out. First, the level of technical expertise, and diligence in maintaining and securing religious web sites may be low, including less technically accomplished owners, farming out tech services to others, less funds for site software and maintenance, and the use of website-in-a-box cookie cutter software (which itself may suffer similar maintenance problems, as they are often created by the same people, and once the software is broken, all sites using it are vulnerable). Another possible contributor might be that religious sites are more likely to attract vandalism and exploitation by people who dislike religion. But probably a key factor is the demographic. If you're looking for targets for scams and frauds, I imagine religious sites might attract a very desirable demographic to exploit.

But again, the differential, IIRC what I read, is not enough to draw any firm conclusions.