Because science works whether or not you are a Christian. Because a broken machine is just as likely to be fixed by a kick as it is by a prayer. Because science is knowledge, not faith.
You are not getting my point. The point is that every one approaches science with a philosophy, i.e. with certain presuppositions that emanate from one's total worldview. A naturalist approaches science with the prsupposition that God doesn't exist and that neodarwinism is true, therefore that scientist will look at every single scientific experiment through that lens and only a naturalistic conclusion is possible. WORLDVIEW is everything. Not all science is created equal, and not all sciece is legitimate. Only a scientist who has the Christian worldview is capable of knowing true science. That excludes all neodarwinists.