Why do so many people fight the idea that humans evolved from simpler life forms?
Perhaps, this resistance is the natural consequence of the "chain of being," the long-time teaching that God and the Angels are the most superior forms of existence, humans inferior to them, and "beasts" and plants more inferior still, with rocks at the very bottom.
[The 1579 drawing of the great chain of being from Didacus Valades, Rhetorica Christiana]
Even though biology does not recognize a status hierarchy among living things, the “chain of being” schematic nonetheless lingers in the minds of some people, especially among people who fail to appreciate the immense biological record uncovered by dedicated scientists, the importance of the scientific method and the elegance of evolutionary theory.
Those who oppose evolution tend to be the same people who go around dissing organisms traditionally plotted lower on the chain of being diagram. A good example would be the (lack of) respect given to sponges. You can almost hear the fundamentalists spitting and hissing as they utter something like the following: "How dare those evolutionists claim that we come from sponges!"
To me, however, this reasoning does not reveal a scientific dispute, but only ignorance regarding the intimate biological relationship between humans and sponges. I find the harsh anti-evolutionary rhetoric of fundamentalists to be, essentially, anti-spongist. Since one can further trace human ancestry all the way to bacteria, I find such reasoning also anti-bacterialist. It makes me want to shout: You anti-spongists! You anti-bacterialists!
The remedy for this attitude problem of fundamentalists is that they need to take the time to honor and appreciate the complexity of "simpler" organisms.