I received an email from my in-laws yesterday, one of those joke ones that people forward on. But this one contained a highly offensive poem about Muslims. I am a bit gobsmacked. I know them to be DM reading types, who have displayed racist attitudes in the past, but not to me and not in such a vile way. If this can be believed, they are otherwise decent people, adn I've no wish to cause a rift. I've ignored more mildly offensive things before, at DH's wish, but it just doesn't sit right not saying something about this one.
How would you word an email to make the point that you regard this 'joke' as highly offensive and unacceptable, in a non-confrontational way?