yitay, I was just preparing an answer and you beat me to it. Exactly. In addition, there are 3 main ways of avodo zoro. 1. bowing or kneeling – this is always ossur, no matter which AZ it is. This includes Xianity, although that may be mi’derabonon.
2. Sacrificing – bringing a korbon, killing the animal le’sheim the AZ, also always ossur. Even though Xtianity has no animal sacrifice, this still applies although again mi’derabonon.
3. Derech avodoh, the normal way of serving the AZ – this is only ossur by doing the service particularly required for that AZ. For Xtianity this will depend on the psak if its a real AZ or only shituf. Thus going for Communion during the Eucharistic Mass may be AZ. Paying rent isn’t any part of any of these AZ ways. And here we go back to what Yitay said about lifnei ivur of lifnei ivur that isn’t ossur. And the company itself paying rent isn’t ossur either. This is because the Church itself, in other words the actual Xtianity concept, doesn’t own the buildings. An American corporation, albeit non-profit, owns it all, including the actual church building. That corporation is “owned” by the board of trustees, some lay people and some clergy. So Wolf, go back to work.