I don't think I am confusing the two. Either you believe the teachings of your religion or you don't.
If you believe that the bible is really true then why would you stray from even one word of it? How do you choose what bits of the bible are truth or just made up? Doesn't that make a mockery of organised religion if everyone can just pick and choose what is the absolute truth or not?
I tell you one thing, if I ABSOLUTELY believed that there was someone up there who was judging what I do every day and he has given me a book of rules that will guarantee my ETERNAL salvation then you'd be damn sure I would obey EVERY SINGLE RULE no matter what. Who are you to decide what rules are relevant or not?
You're committing the Straw Man fallacy by suggesting there is a single entity called Christianity, with a single set of beliefs, and then proceeding to attack it. That's total nonsense. When you say Christian teachings, which teachings do you mean, exactly?
For example:
1. Catholics believe the Pope is God's representative on earth, and will take his interpretation of the bible over the words written in it.
2. Fundamentalists believe in the literal word of the Bible above all else
3. Eastern Orthodox follow a group of patriarchs who they believe to be equivalent to the apostles.
And that's just 3 of however many dozen Churches there are. All of those Church members would describe themselves as Christian, all have slightly different beliefs. Some believe in evolution, some don't. The Church of England, for example, has a made a public statement accepting evolution, and saying that ID shouldn't be taught as science.
Even if you describe Christians as "people who follow the Bible", which Bible? It was originally written in ancient Hebrew, Greek and Aramaic, and has been interpreted, translated and adapted for modern use into hundreds of different versions.