I used to ask the same kind of questions, but I have come to see them in a different light. I'm not suggesting that the subject matter of such questions is the problem, I think our basic misunderstanding comes from an assumption that claiming a specific teaching defines faith. Bear with me just a bit on this because I think it will answer more of what you're really asking here, though I will also address the subject matter after this, okay? :)
We have come to speak in terms of believing when the word "opinion" would more accurately describe our relation to the concept or idea that is being discussed or declared. But we don't usually want to say we THINK, or that this thing is our opinion because it sounds less authoritative or less personal or perhaps, less godly and more scientific. The fact of the matter is that our religious world has presented us with the idea that our beliefs consist of the teachings we hold, instead of IN WHOM we believe - and this has created MANY bogus ideas. Are you following me so far, or does this sound too off the wall? Don't be afraid to simply tell me that, okay? :)
Now, the thing religion has used in promoting this bogus concept is the Bible. Many of us have been weaned on the notion that, "If the Bible says it, I believe it!". I sure as heck remember saying this, and I can remember how right it seemed. After all, I ASSUMED that in claiming this I was standing in agreement with GOD, but in many ways I was only standing in agreement with my current teachers. The sad reality is that those who disrespect each other the most are often those who make the strongest claims regarding holding to the Word.
Why do I think this is so? Simple. We were presented with the idea that if we wanted to believe God we had to believe the Bible which meant that we had to find out what the Bible taught so that we could take a stand upon it so that we would know whether or not what we believed was true or not and if we did not believe what we were being taught we were not believing God and we didn't want to find ourselves standing against God. To compound the problem we have used the Holy Spirit's enlightening of our understanding of the Bible to support our beliefs so that for us to consider that our view is wrong is to suggest that God is wrong since it is what He revealed to us.
I think one of the main reasons we often claim to believe certain contrary teachings is simply that we have assumed that believing otherwise constitutes disbelief on our part, and so we hold onto it even though something inside is cringing in the process. There is usually a Bible verse or a teaching built upon a few cross-referenced Bible verses that encapsulates the particular truth in question. Bottom line: FEAR of infidelity toward God has caused many of those in Christ to hang onto many false concepts of the flesh that had resurfaced as Biblical truth.