Why do Christians who don't believe in evolution, totally denounce it?

Some people believe the Bible is literally true. They read the Bible to say that the earth is only ~ 6000 years old. Evolution, biology, geology, astronomy and many other sciences provide abundant evidence that the earth is much older. I do not know why the issue of evolution is the one we hear about most often but someone has to disregard a whole bunch of scientific evidence to believe that the Bible is literally true.