Because God is something that must be taught, which is why there were no Christians in America before the European settlement, why you don't see Christian writings in Ancient Chinese, why the Aboriginal Australians aren't all Christian, etc... ad infinitum. Christianity can only spread through teachings about it. If you take a newborn child and never mention "God" that child will never know what God is until someone gives it that name. Thus atheism is the default state of man.
A belief in the Christian God isn't the only form of religious belief in history. There were no Christians among the Native Americans before the Europeans came, but there were probably very few atheists too. They had lots of creation myths of their own. Same with the Chinese and the Aborigines, they were all generally religious people. If you had asked them if they believe that spirits exist, or even that a Great Spirit exists, they would mostly have said yes.
2. As I said before, the Evolutionary Theory is the description of the innumerable instances of evolution throughout terrestrial history.
Did you say this before? You only said: "A theory is defined as a working description of scientific facts." Genetic mutation is a scientific fact, yes. But "innumerable instances" of genetic mutation leading to the evolution of fish into amphibians, amphibians into reptiles, and reptiles into birds and mammals is something that can only be proposed based on the interpretation of a number of fossils.
4. No, you have seen things. It's up to you to prove that they could have only been done by God. I haven't seen anything, so I have nothing to prove.
Go visit a Pentecostal church sometime. You might see something that would inconvenience you. As it is, you seem to be claiming there is no such thing as light because you've never tried to open your eyes.