How do you approach any person? By trying to understand who they are, and making your points from a perspective that they know and understand.
This Jesus character had some very intelligent things to say. It's worth learning, and even impressing your fundamentalist neighbours with, if you can pull off a few quotes.
If you find that trying to understand Christians is distasteful, then I put it to you that your reaction is emotional, not rational. Treat it like a science experiment, if you want. The aim is to try and discover methods and practices which make for a more congenial fundamentalist neighbour. It's possible, especially if the religion has a love and acceptance factor built into it.