A Christian is a follower of Jesus Christ and His teachings through the Bible. If a person is not following in His footsteps then I would question his faith as a Christian. There are people who consider themselves Christians, but don't walk the walk, as is the case in the Crusades or whatever historical event that you may think of. Obviously there is more to it than that. It's like claiming that you are scientist, but don't follow the rules of Science (such as making a hypothesis). Standards of practice were created because people weren't proving what was being hypothesized. Christians go by the Bible as their standard of faith.
I would agree with you that there is no hard scientific data (i.e. mathematical equations) that God exists. I only see the order that is in this world, meaning you can scientifically equate 99.9% (not sure if that's a good number) of our surroundings. That's why Science exists. We have math, physics, chemistry, etc .. because the world has order. Faith can not be translated into numbers. Faith that a Creator exists can be proven, but not scientifically, or else it would not be considered faith.
Please, don't insult my faith. I'm just asking a simple question that warrants a complex answer. Some Christians have become power hungry, I agree. The true Christian calling is to walk in humility to serve others, just as Jesus came to serve.
I'll apologize for all those Christians that have set a bad example. I hope you understand that there are Christians that walk the walk and I hope that you meet one of them one day. Peace bro.