"There's a reason that Catholic schools (well, most of them anyway, I'm sure there's exceptions) teach evolution"
I think they teach evolution because evolution is covered on mandated state testing. The tests are created by boards who are appointed by the state. All students are required to take these proficiency tests.
It is my understanding that most Catholic schools teach to the test (the thing liberals claim is wrong when it comes to No Child Left Behind) because they are forced to by the states. I think most Catholic teachers also disclaim by stating "this is what we are forced to teach you" or "this is the other point of view", something that the public schools would never do (ie, provide the "other" point of view").
Well now, I went to Catholic school from K-12. We learned evolution in science class, we learned religion in religion class. We got an amazing education, in fact, college was a joke to me, 4 years of minimal work and a degree to boot.
Why do Catholics not believe in creationism? Probably because we embrace learning, logic, science and free thought, and we aren't so terrified that some actual data may destroy our faith.
But, if you want to believe in Noah's ark, go ahead, just don't teach your fables in public schools.