Arguing against the existence of God is just a waste of time.
No matter how convincing your arguments are, they are going to be meaningless to a believer.
Even the brightest scientist in the world would not be able to convince a true believer.
Why? Because you're speaking a different language. Religions don't speak 'empiricism' as we normally do in Science, and their language is simply the words of God.
To them, whatever the God says is right and true.
So whatever we, the ones who pursue Science, say to them is absolutely meaningless.
In scientific view, the believers have a 'theory' that can never be tested or be falsifiable. So again, whatever they say to us is absolutely meaningless since science puts no value in such theories.
That being said, although I am not religious to any degree, I still find some values to having religions. You mentioned that "religion is just a way to put distance between people of different ethnic backgrounds", but I disagree. Different culture is what really puts distance between people of different ethnic backgrounds, and religion, quite ironically, can actually break some of those cultural barriers. For example, many White people, Asians, and Black people are Christians, and so they can be quite interactive. Of course, you would be right if we were only considering some of the other religions that are kind of restricted to limited groups of ethnicity.
Recently, I've heard this rumor that religion is fading away in many developed countries (I haven't checked this out myself though)
Since science is the only thing that is improving everyday, I have this strong belief that religions will eventually disappear in distant future before human civilization disappears. But again, humans are weak, and we need some Godlike figure that we can really rely on. So I'm not 100% certain with my belief sometimes. One thing I can guarantee, though, is that the number of believers will decrease eventually, at least in developed countries.
Just be patient if you don't like religions
