OK, here is another place to give my "Phantom Menace" concept. The bottom line is that the essentials are STILL held and they are held to the same degree. Do you think you believe in the resurrection more fully than I do, or that we are sinners in need of redemption, or any of the other handful of essential "salvation" issues of belief? Of course not.
It seems to me that the majority of the Creationist platform is based on the fear of a Phantom Menace. So often, when a topic is raised, whether it be interpretation of Scripture, the Fall of Man, a literal Adam, etc, etc, the argument that Creationists will eventually fall back on is a slippery slope/phantom menace position. They will acknowledge that a belief in evolution, or figurative Adam, etc, is not itself a "salvation" issue, but soon we see this "menace" argument come out.
I will give some examples and in each, consider X something that is not a "salvation" issue in and of itself (an old earth, evolution itself, a figurative Adam, no global flood, etc), but Y *is* a salvation issue. Here is what we end up hearing:
"Well, if you don't believe X, then how can you believe Y?" [or even, "you can't possibly believe Y."]
"A belief in X means you reject A and B, which means, ultimately, that you reject Y".
"You can't truly have faith in the truth of Y if you believe X".
"A belief in X will lead to a disbelief in Y"
"The whole concept of X does away with the need for Y".
And numerous other variations on this theme. Not only does this rely on a slippery slope (which ends up being not as slippery as they think), the entire "menace" is a PHANTOM menace, since all of these statements are almost immediately falsified. It is shown over and over that those who DO believe X almost always still believe Y. Just because a given Creationist can't imagine how someone can accept Y when they also accept X doesn't mean a thing. The facts are the facts.
Those Christians who accept all those X's tend to believe (and believe just as strongly) in every orthodox essential for salvation. Their belief in evolution, or a figurative reading of Genesis, or a typological Adam, does not seem to do ANY damage, whatsoever, to their faith in anything essential for salvation at all. Yes, there have always been those within Christianity who hold unorthodox beliefs, as much before the advent of this debate as now. But the fact that millions of Christians entirely accept evolution and have NONE of their essential Christian beliefs undermined is a plain and simple falsification of the phantom menace.
The bottom line is that any rejection of an idea or concept based on "what the effect will be on other beliefs", is only a valid objection to the extent that effect actually is observable. In the case of Creationist arguments, it is NOT observable. We are still Christians, and devout, committed, Bible-believing, Spirit-filled Christians at that!