Just wondering, what are you using to write this? Presumably a computer or a phone, something that exists because of human ingenuity and many years of scientific endeavour. Everything in the modern world is based on science that actually does something, and is not "mostly only theory". Do you live in a house? How was that built? Do you use a car? Electricity?
Science is not "mostly only theory"; it's the bedrock of the modern world. Whereas religion is simply an anachronism, an outdated simplistic mechanism of social control.