How do I accept my mother's religious beliefs?

My mom and I get along pretty well, but that hasn't always been the case (I'm 32). I've learned to deal with the facets of her personality that make it hard to have a relationship with her. There is just one thing left. She is a member of a religion that I am not fond of. I was raised in it and all of my siblings are currently members. It's basically one or two steps up from being a cult. I feel like she is brainwashed and it drives me crazy. Sometimes she says things and I feel like I need to respond. I don't know how to explain it. I guess it kind of feels like having a friend who is in an emotionally abusive relationship and they mention something offhand that their partner did and you feel obligated to say "that's not ok". My mother invariably has a response based on the beliefs and usually then shrugs or changes the subject. This drives me insane as I've read about this and I know they utilize a technique to train the followers to shut down a thought process when it conflicts with their teachings. I know this sounds a little crazy. It is a somewhat mainstream religion, but if you've been a part of it and no longer are, you can see some crazy stuff from the outside looking in. I can't seem to help being extremely bothered by this. I just want to shake her and say "Can't you see how crazy this is? Can't you see how they manipulate you? Can't you see how ugly they make the world look for you?" Why can't I just let this go?? Any suggestions?