Everyone knows that churches tend to self-segregate. Amongst Catholic immigrants to the US, you see that there was/is an inclination to segregate themselves from Catholics of a different ethnicity. The Irish didn't want to go to the Italian church or vice versa.
Something odd about the Catholic church is that – for a church which has a legitimate claim to being the one true church – it's not all that interested in converting people. Why does 'RCIA' take so long? Why do they never attempt to actually convert the 'Protesters'? Now Catholics will come up with many creative reasons and quotes to justify this. "At all times spread the Gospel. When possible, use words." But if you press them on it, they may admit that some segment of their churches just isn't that interested in getting 'others' to attend church with them. The reasoning behind lengthy catechesis is same reasoning behind the Jews making you get dick poked after learning Hebrew: You, convert, are a potential racemixer. /pol/ logic rests at the heart of most religious organizations.
This holds true outside of the Catholic church as well – even if they don't mean for it to. The Baptist Church and evangelical churches obviously want to convert people. They would convert all of the other types of Christians if they could. But most of the people who end up in such churches belong to a certain class of folk: not WASP, and not Catholic. These people are mostly working class, and mostly English and Scottish with a few random Germans/Scandinavians thrown in along the way. They have different opinions on everything from their WASP brethren, and you couldn't rightly consider them to be from the same sector of society.
This tendency amongst the religious used to bother me, but I've learned to accept it. Keep in mind that God understands most people are dumbasses. The IQ 95 person who's convinced that their random Protestant sect is the one true religion doesn't know any better. They love God in their own way, and they worship him in the way that their 'people' deem fit.
For those of you who are thinking of changing denominations because of some minor theological issue, don't. God wants you there in your socioeconomic group backing up the normalfags he put around you. Without good shepherds, who knows how lies from Satan they'll be takein in by?