it is easy for all the rest of the religions to make money off the atheists.
That's true. Every time an atheist steps into a church, he feels guilty for not believing and thinks a donation to the cause will make things right. Of course, the faithful know you can't just buy your way into Heaven, and so never give their money away for such foolishness. Tithing is for sinners. That's how it works, right? 
But the benefit is that many of the churches use the atheist donation to help convert the atheists to Christianity. This way even atheists have a better chance of becoming theists and getting to Heaven. And it works out nicely for the theists, because the atheists were self-funded by their church donation while they were still atheists.
