I have always wondered why christians Halachily are grouped, since they do not all have the same beliefs
For example
There is a group called Unitarians who do NOT belive in the trinity, Would you be allowed to go into a unitarian church (Like you can into a Mosque)
Icons are only in Catholic , Lutheran and Episcopalian (Angilcan) so the others dont have Statues and some of their churches are rather plain