What interpretation of the Bible? You can't just focus on Matthew 7:12 and Luke 6:31 and say "That's it! That's all there is to Christianity!" From an objective point of view, those passages don't even make sense -

So in everything, do to others what you would have them do to you, for this sums up the Law and the Prophets. -- Matthew 7:12, NIV, other translations are similar

The fact that 4 of the 10 great commandments are specifically addressed towards worshiping God contradicts this. Is there any way to interpret those 4 as being a form of "do unto others as you would have them do unto you"? No.

Same with so many of the other laws, such as the purity laws (e.g. food restrictions, cleanliness restrictions, virginity, etc.).

How is the Law's apparent acceptance of slavery in line with this 'Golden Rule'? How is Jesus' own refusal to condemn slavery, despite his parables and his culture clearly involving slavery, in line with this 'Golden Rule'?

he's hardly a Christian if he doesn't even follow the Bible.

Hmm.

Therefore no one will be declared righteous in God’s sight by the works of the law; rather, through the law we become conscious of our sin. But now apart from the law the righteousness of God has been made known, to which the Law and the Prophets testify. This righteousness is given through faith in Jesus Christ to all who believe. There is no difference between Jew and Gentile, for all have sinned and fall short of the glory of God, and all are justified freely by his grace through the redemption that came by Christ Jesus. -- Romans 3:20-24, NIV, emphasis mine

By your definition -- that is, whoever does not 'follow the Bible' is not a Christian -- then no one is a Christian. No one follows the Bible perfectly; no one even follows their own interpretation of the Bible perfectly.

Yet this passage very clearly states that "righteousness is given through faith in Jesus Christ to all who believe"; if he simply believes, then he is righteous in God's sight regardless of his actions, or so claims the author of Romans. If being righteous in God's eyes does not make you a Christian, then what does?

I mean that - what is a definition of a Christian that applies to, and only to, Christians (i.e. includes all Christians, excludes all non-Christians)? And here you get to the crux of the matter: 'Christian' is a concept created by humans, and defined by humans. Like other human conceptions, the definition is a fluid, amorphous amalgamation of tradition that is really not definable in an objective fashion. Unlike the No True Scotsman case, where you can at least get a lot of people to agree on a definition of what a 'Scotsman' is that is demonstrable (someone who was born and raised in Scotland, for example), there is no easily defined tangible boundary for Christianity - only a vague notion of 'belief'.

Disclaimer: I'm an atheist who was raised in an extremely well-read Christian family. I've gone to Christian schools my entire life, including a Christian college with a seminary. I have no doubt that Pat Robertson considers himself to be a Christian, and that he has plenty of scripture to prove it to himself (and to the millions of those who follow/followed him as a Christian leader).

If you want to keep debating this, I'm game.