We do understand what Christians believe. Many of us were Christians, and even those of us who were never religious probably know more about different religions (including Christianity) than the average Christian. That's what happens when you rely on documented evidence, reliable information and proven facts instead of feelings, rumor, myths, and hearsay.
The "church is the miracle now" excuse is pretty lame, if you excuse the pun. If any church group or denomination had any success (beyond random chance) in doing anything miraculous we would know about it by now.
Unless they are somehow keeping all the magical healings of soldiers with traumatic brain injuries, children with Down's syndrome, and babies with cleft palate a secret from the world. If the awesome goodness and power of Jesus or god was really floating around the world, there should not be any brain injuries, birth defects or warfare to begin with.
The fact that the world still sucks a lot of the time for a lot of people, unless other people directly intervene
, is pretty clear evidence that we human beings are on our own.