If we are forbidden to covert Moabite men, (but the women are permitted because they were not involved in the offense to the Am Yisrael), how do we know who they are? I heard something a couple of years ago claiming that the Chinese were the descendants of the Moabites. How do we know if we have as a people "collected" as it were, gerim from this forbidden group?
Hadassah, the Gemara states clearly that Sancheirev mixed up the whole world so we follow the rule of majority and most people in the world were not Moabites. I guess we gotta thank Sancheirev for something :)