I don't even touch pork. (if touch it by accident, I wash my hands with lots of soap) And I don't mind if someones is offended, if I am served pork, I shall reject it, just to be an example to Jews. Many Jews claim that it's unpolite to reject it, and eat Tumah.
Regarding pork and shellfish, I don't know if they are unhealthy, but the Torah says they are filthy. Only that a goy is not bound to avoid filthiness. But would you eat something dirty even if it is no sin?