If you believe in God then you must believe that God can create anyway he wants to create including letting an evolutionary process procede. Why does there seem to be a contradiction here?
Because certain people, like IDists and creationists, want to place limits on God.
Because some people have their view of religion controlled by numerology. They believe that God must follow a certain numerical pattern and you can use numerology to determine what God will do next. For example, the number 7 is believed by some to be the perfect number, and this means that God will destroy the universe when it is 7,000 years old and create a new heaven and earth. That is why the "young earth" creationists believe that the earth can only be several thousand years old. I know I am being terribly simplistic and unfair but it comes down to the idea that some system of numerology can explain everything.