In addition to your source's ignorance, He also makes no valid point. Have you never heard of non-denominational Christians?
Once again I'll say just because he isn't what you view as a Christian doesn't mean he is not.
You appear to be saying that: what Christ taught in the NT doesn't provide a basic understanding of what constitutes Christianity... correct?
What Breivik did -vs- what Christ taught in the NT aren't even remotely close, bro... why wouldn't "non-denominational" Christians agree on this one?
Mathew 7:16-20