[tristor]

> I'm curious about this. Why not?

I also have friends that are on restrictive diets or who don't drink and I invite them out with me regularly. The reality though, is that many people take personal choices and turn them into a religion that they then feel the need to proselytize. I simply don't spend time with people like that, but I can imagine those are the sorts of people grandparent has in mind when they wrote that comment.