That may be true of a small number, but I doubt that many people think, "I want to sin a lot, so I'd better not accept Christianity".
Surely you will at least admit that SOME people reject scientific knowledge without any serious inquiry just because they do not want to face the possibility that their religion teaches falsehood.
To believe Genesis I is a literal description of what happened c 6000 years ago is to ignore all other objective evidence that we have managed to collect. Why did God make the universe seem ancient to open-minded seekers after knowledge? As one easily-understood and hard-to-handwave-away example how would you reconcile SN1987A with a 6000yo universe?
This really gets to the heart of the matter. Do you believe people have the ability to make choices or that everything is fate?
Of course people have the ability to make choices, and should take the responsibility for their own actions and decisions. But Christianity says that we will fail to avoid sin, no matter how hard we try. Why should we be punished for an unavoidable failure?