Compromise On The Beginning Is Significant

Therefore, the old-earth creationists' method of interpreting the Genesis text actually undermines the historicity of Adam. Having already decided to treat the creation account itself as myth or allegory, they have no grounds to insist (suddenly and arbitrarily, it seems) that the creation of Adam is literal history. Their belief in a historical Adam is simply inconsistent with their own exegesis of the rest of the text.

What "old-earth creationists" (including, to a large degree, even the evangelical ones) are doing with Genesis 1-3 is precisely what religious liberals have always done with all of Scripture—spiritualizing and reinterpreting the text allegorically to make it mean what they want it to mean. It is a dangerous way to handle Scripture. And it involves a perilous and unnecessary capitulation to the religious presuppositions of naturalism—not to mention a serious dishonor to God.

Evangelicals who accept an old-earth interpretation of Genesis have embraced a hermeneutic that is hostile to a high view of Scripture. They are bringing to the opening chapters of Scripture a method of biblical interpretation that has built-in anti-evangelical presuppositions. Those who adopt this approach have already embarked on a process that invariably overthrows faith. Churches and colleges that embrace this view will not remain evangelical long.

~John MacArthur

I would suggest that they aren't evangelical at all. They are attacking God and His Word just as Satan did in the Garden with Eve--and for the SAME THING: knowledge outside of God's Word: "Hath God said?". Their faith MUST be questioned:

Heb 11:1  Now faith is the assurance of things hoped for, the conviction of things not seen.
Heb 11:2  For by it the people of old received their commendation.
Heb 11:3  By faith we understand that the universe was created by the word of God, so that what is seen was not made out of things that are visible.