Why do religions deserve more respect than other preferences, such as dietary choice?

Intellectual conversation is always acceptable. I think, personally, the problem stems from the idea that we can't all be correct, therefore, people tend to become a little sensitive about certain issues. In most religions, questioning one's faith is often considered counterproductive. Members are encouraged to feed on spiritual knowledge, not question it. And, consider your question. You say specifically, "corrective conversation." Many people do not recognize a difference in corrective conversation and criticism. By the way you pose your question, I think some may find your "corrective conversation" critical at the least if not accusatory. There's a big difference in discussion in the pursuit of knowledge, growth and understanding and "normal human corrective conversation." An exchange if ideas is often more productive when it doesn't sound so...ummm...critical. And frankly, if you're making fun of people for eating escargot, or haggas, as innocent as it sounds, you have most likely offended someone, tender creatures that we are. None of us like to be made fun of, regardless of our spiritual pursuits or even, dare I say, our eating habits.