Evolution or Creation is actually irrelevant to the Question: "Why Does Science Need to Prove or Disprove The Existence of God".
Especially arguing against particular US viewpoints on "creation".
Anyone that regards The Book of Genesis or the Creation theology or writings of any religion as literally historical scientific claims is making the same mistake from a different starting point.
"Creation vs Evolution" is totally pointless debate:
1) "Creation" can mean nothing to Science and you can move the goal posts to suit all known facts ("God as Watchmaker")
2) "Evolution" is a scientific attempt to explain development of species etc from Single cell thingys to stuff today. It says nothing about God. Nor does science answer questions like "what is the point of it all?" It's like trying to decide if the Mona Lisa is a good painting by analysis paint, or advocating taking care of the poor by explaining how babies are produced.
Religion, Torah, Old Testament, Koran, Buddhism, Hinduism, Jain, Theology are not God. They are Man's record of trying to understand God, no matter if you are believer and think the writing is inspired by God OR are an Atheist convinced God is delusion not fit for "Rational" beings. Evolution has no knowledge of Rational. It's just a description of what has happened and an explanation of why that happens without having to invoke a "god" directing it. If there is no God, then Gaia too is a myth and evolution is no more philosophically important than how a Sun 'burns' hydrogen to helium, we are no more of significance than a bacteria, just complicated enough to realise we aren't the same and ask why?
By definition you can't "prove" God exists or is imaginary. Poking fun at primitive theology says nothing about God and only proves that some people that believe in God are not very logical, or well educated.
Dawkin's "evangelical" Atheism is his starting point in interpreting Science and some of it embarrasses Atheists.