it is not about whether actions or faith make someone righteous. it is about christianity being defined by faith, not actions. we don't call someone a christian because they are righteous, we call them a christian because they profess belief.
You said earlier that faith produces love, works, etc. That's all fine, but here you say "we don't call someone a Christian because they are righteous," but Christ says that we call someone a Christian because they love one another. You can say faith produces love, but faith can't be seen. Love can be seen. Professing belief is utterly meaningless.
Thus, you may call everyone who professes belief a Christian, but a lot of people don't agree with you, and Christ is among them.
"Not everyone who says to me Lord, Lord, will enter the kingdom of heaven, but only those who do the will of my Father in heaven."
The profession of the Pharisees is that they were sons of Abraham. The profession of Christ was that they were sons of satan, vipers, hypocrites, disciples of hell, and several other none-too-favorable epithets.
I remember talking once with someone about faith in Christ, and a co-worker came in and joined in with me. The person I was talking to said to the co-worker, "I don't want to hear anything you have to say, because you're a hypocrite. Go away." My co-workers profession meant nothing to this person whose actions did not match up with his profession. I think most people feel that way.
Thus, I also disagree with your statement that:
if we are judged to be christians or "not christians" by the heinousness of our deeds, then we will all fall far short of the mark.
That is not true. Maybe none of us are perfect, but I have always been able to produce a list of people I knew who didn't fall short of the mark at all by my standards, and another list of people who are nothing but stinkin' hypocrites. Others are in between, but I've always known people who do not fall "far short" of the mark, but are wonderful representatives of the faith they profess.