Dear Hakatan,
1) I have discussed Zionism with you multiple times. You can’t back up your position even a little. For you it comes down to this. If a zionist rabbi does it, then he is wrong because he can not be trusted to have a justification. But if an anti-zionist rabbi does it, than we give him all benefit of the doubt. An interesting wrinkle in hilchos loshon hora. Silly opinions give legitimacy to slander.
To further make the point. If the Ponevezh RY and the Gerrer Rebbe would do it, than it would be assur for OE or YU to think they did an issur because to them they are great talmidei chachamim who deserve the benefit of the doubt no matter how outrageous the circumstances appear to be. But for Satmar and Brisk, they can judge the matter at face value because they are more anti-zionist than Ponevezh and Ger.
2) Going into a church is because of one of two very basic reasons. A child could understand them. There are dozens of precedents from all different countries. I’m not going to discuss them, because I don’t want to imply that there is a permissiveness about this issue.
Your theory of splitting halachah based on ideology, does not have precedent. Oh wait! It happened before. It’s called The Great Schism. Which took place in ………………….a church.