Who are the real Christians?

More fascinating to me than the sordid story of the New Hartford NY "Word of Life" church where two parents in the congregation joined in beating one of their sons to death and beat another nearly to death, reportedly in order to make them confess sins, are the comments the news have attracted. Two themes predominate: masters of the obvious reassert the stupidity of religion, while apologists for Christianity attempt to demonstrate that the Word of Life congregation aren't "real" Christians. We see this any time professed Christians do something abhorrent, and while it's obvious that many Christians can't imagine perpetrating an atrocity like this one, it's also unclear how their admirable scruples entitle them to excommunicate the perpetrators. Post-Reformation Christendom, outside the Catholic Church, is a "priesthood of all believers" in which no one Christian can authoritatively deny another's prerogative to interpret the Bible according to their own lights. Scripture was rendered into the vernacular tongues of Europe, and then those of the whole world, just so no literate person had to take a priest's word for what the Bible said. A proliferation of denominations, sects and cults was inevitable as interpretations diverged. Often, at the end of the trail, believers choose submission to some compelling interpretation and enable "cult" leaders to dominate their lives in totalitarian fashion. Appalled observers can offer any number of reasons why such submission and such lethal obedience are wrong, but what authority have they? What makes their interpretation of scripture superior or more compelling than whatever prevailed at the Word of Life church? Doesn't the Old Testament authorize parents to kill disobedient children? What verse of the New Testament actually abrogates that mandate, as many presume the Gospels must? All these apologists can really say is that they're not violent or barbarically patriarchal, but nothing else follows from that. In the absence of universal submission to one religious authority or universal consensus on the exact meaning of all scripture, Christians, however well-meaning and properly indignant about this horror, have no more right to say that the perpetrators are not "real Christians" than Muslims have to say that takfiri terrorists and honor killers are not "real Muslims." But if Christians want to make such distinctions, they should be willing to recognize the distinctions made by others and give some benefit of the doubt to those Muslims who insist that terrorists and everyday barbarians aren't real Muslims, rather than assuming, on far less knowledge than they can claim about Christianity, that they know better than Muslims what Islam is all about. As somebody said, sort of: if you don't want to be judged, judge not.