Jeff, I think this is a good move. Too often I have seen authors approve inappropriate comments because they do not want to censor anyone or control the conversation. The comment is not "spam", so they let it through.

When you have people from many different cultures and backgrounds trying to communicate, and you want them to feel able to get involved, you have to go for the highest common denominator, which is being respectful and polite.

Rather than use the contact form to inform the author of a comment problem, I would suggest a "report a problem" button or link in the comments section, perhaps discretely under each comment next to the "Reply" button.