And if we compare an occupied house with an occupied church, or two empty ones?
Would depend on how the church was being used. Church is still a church if 'occupied' just means 'there's a dude squatting in it'. Some folks convert churches into homes, business buildings, etc. Church is a style of building as much, if not more, than a function of one. Also what you mean by 'empty'; in the sense that there's no one there
right now, or in the sense of an abandoned building. Former, in that case, would be worse than the latter.
Beyond that, depends on how much the building
cost. Churches usually cost more to construct than your average house (Which smacks of either hypocrisy or heresy for some religions, but that's neither here nor there, I suppose.). From a strictly material point of view, you're usually doing more damage wrecking the former.
Then, it'd depend on whose house it was. Burning down the dalai lama's place of residence would be different from burning down, say, mine, as an example. It would also probably be worse than burning down some number of churches-of-equal-occupancy-status. The same might be said for a particularly effective doctor or scientist, depending on their accomplishments.
Last part, I guess, would be the status of the church. There's (active) ones in my area that a significant portion of the population would cheer from being burned down. They can be as much a source of dissension and strife as community building, sometimes. You'd probably not value a widely reviled church as much as a widely appreciated one (Though it depends on the reasons for each, of course. Hence the probably
).
Multi-variant situation! The answer is 'depends'
I'm not sure why we're ranking crimes at the moment, other than explaining why burning a church is different than burning other buildings.
Because it's fun! The original burning subject didn't even have anything substantial to do with the building being a church, really. Community center would have had the same effect (possibly more) in some areas.