The Bible condemns homosexuality.

[Jehanne]

Your daughter is not going to Hell when she dies; instead, her remains will, we all hope, be intured next to those of her beloved lover.

That's why she should not kill over a despicable falsehood.

Well yeah, she doesn't believe that she will.  But the argument is: If it's all true, why shouldn't she?

It's a non-sequitur; it's not true and you have better things to do with your precious time than to play with Professor Farnsworth's what if machine:

http://futurama.wikia.com/wiki/What-If_Machine