Could it be that Dr. Purdom limits her research to avoid a conflict with her religious belief? She seems to want to stop at a point where an untrained audience might get the impression that point mutations stall at the micro-evolutionary stage. She would thus, knowingly or not, be building a platform to refute macro-evolution that would appeal to the untrained audience.
Speaking as a Christian, I fear that the issue is willful ignorance at best, but more likely just plain money. There is a gold mine out there speaking to and writing books for the Christian Cult of Ignorance groups.
Anyone so limited that they can only spell a word one way is severely handicapped!