After looking at the numbers, I suspect that the major factors were name recognition and the lying, not creationism.
I, as a teacher in the field, would have no problem with a simple statement to the effect that the tenets of evolution at this time may appear to conflict with some people's religions, but that in this class we are learning what the current views of scientists are.
That is honest and respects the religious concerns, without in any way diluting the science.
I would guess that most people who believe in special creation, unlike those from DI and many of those who promulgate it here, are honest and react badly when the dishonesty is put on display.
It think it was "Pandas" promoted as a science resource that moved Dover into unacceptable territory.