Nonsense. If the Church et al. considers them non Christian, why should you ?
I assume you meant to ask, "... why don't you as well?" Who says that the church considers them non-Christian?
Even if that is correct, that the church also engages in the same No True Christian argument, it is irrelevant. Try to imagine hearing that argument come from Muslims about Muslim terrorists: they're not Muslims.
Let me illustrate your double standard here to you. When I just used the phrase, "Muslim terrorist," did you bristle at it like you did at the term "Christian terrorist"? I'm going to bet that you didn't. If not, why not? What's the difference? Why does terrorism erase your Christianity but not you "Muslim-ity"?
There is no difference to me, but there is to you and, if your claim was correct, the church as well. The difference is that you and the church promote a pro-Christian but not a pro-Muslim agenda, and I have no reason to do that or make that distinction.
Those core beliefs include not doing what they did. Thereby, by your own method they cannot be Christians.
That's your position, not mine.
If you Google "core Christian beliefs," you will see a variety of sites that list items like this:
• Jesus is the Son of God and is equal with God (John 1:1, 49; Luke 22:70; Mark 3:11; Philippians 2:5–11)
• Jesus was born of a virgin (Matthew 1:18; Luke 1:26–35)
• Jesus lived a perfect, sinless life (Hebrews 4:15; John 8:29)
• Jesus was crucified to pay the penalty for our sins (Matthew 26:28; 1 Corinthians 15:2–4)
• Jesus rose from the dead (Luke 24:46; Mark 16:6)
• We are saved by the grace of God; that is, we cannot add to or take away from Christ’s finished work on the cross as full payment for our sin (Ephesians 2:8–9)
These are all metaphysical concepts. None relates to behavior, all to belief.
I couldn't care less about "authority" and why you even brought it up I don't know.
Because your tone assumes an authoritative position in the discussion. You post as if you think that your opinions about Christianity are authoritative. You give yours, I give mine, and then you complain that I disagree as if I have a duty to accede to you.
I also believe you are totally hostile to the principles and beliefs of Christianity, and thus to those who hold them and practice them.
I am opposed to organized, politicized Christianity, and not its principles or beliefs, but its actions. That is a result of my American experience. I despair at the anti-scientism, the misanthropy and nihilism, the mean-spirited homophobia, the incessant efforts to pierce the church-state wall (a very timely objection), the sense of Christian privilege (how dare you atheists put up a billboard next to ours, wish others a happy holiday instead of only Merry Christmas, want to put up a holiday display nest to our creches, or give an invocation that a Christian is supposed to give), the persecution complex (the world's only oppressed majority), labeling atheists as immoral people that have no reason to be ethical and therefore are not, the war against sex education, and more. I am concerned about an ideology that teaches that world destruction is a good thing - something to be welcomed and gleefully anticipated.
I see no value to having this institution in our presence, and a lot of harm. It's divisive and tribalistic. It's like kudzu, attempting to invade and overgrow everything else. It is an unwelcome neighbor.
What else apart from politics would bring you and I to argue like this? Baseball? Plans to colonize Mars?
A logic syllogism proves how wrong you are. Christians cannot commit murder, Bill committed murder, therefore Bill could not have been a Christian when he committed murder. The simplest syllogism, but it proves how illogical your position is.
I reject the major premise. Your syllogism is valid (if the premises are correct, so is the conclusion), but not sound (the premises are not correct, so the conclusion cannot be).
I think many of your humanist/atheist ideas are destructive and even depraved.
Go ahead and name a few of my depraved ideas.