How to tell overly religious people you don't care and don't want to care about their religion without sounding like an a**hole

I may hate religion for the most part, but I do think that everyone has a right to believe whatever they want. The only problem I have is when people come and try to preach to me. I'll give you an example, I was talking to some people at a hotel party and they turned out to be Christians. At one point I said that for example if someone in your family or friends has a different religion than you that shouldn't bother you at all. Their response was "If you see someone you love going down the wrong path wouldn't you do everything in your power to show them the light". At this point, I was thinking ok this talk is pointless. They seemed to believe they were right and everyone else was wrong. Oh and also they mentioned how being a good person in life is not enough, because if you don't believe you still go to hell...
So how do I reason with something like that without being a jerk? And don't get me wrong I have also met Christians who are very nice people, never preach to you, respect your own beliefs, and never talk in absolutes, I am talking specifically about the extreme ones.