Why do christians think that without god there would be no morals? Isn't that hypocrisy?

OK so I noticed that they think that without god to reward with heaven and punish with hell there would be no morals? Isn't that a bit of a hypocritical statement. Basically they are saying that they would do all sort of things considered "immoral" if they didn't go to hel for it, which means that they actually WANT to do all these things. If they do, what's the point of sticking to the god idea if they choose beliefs based on emotions anyway. Not to mention the fact that they are the immoral ones.