the reason an elephant and lion dont mate is because they are different species. and bird of a feather flock together because a robin and a bluejay are also different species. different types of dogs, however, can mate, because they are different breeds, not different species.

unlike a lion and an elephant, a chinese person and a black person are obvioulsy of the same species. it is perfectly natural for them to mate.

back to dogs - mutts are great and can be very cute. but what fun would it be without purebreds too? we wouldnt want to lose our collies and labs and have all dogs to look the same, would we? it also would be a shame that if thousands and thousands of years from now, all people ended up being the same tannish hue. we could only read in history books about black people, chinese people, white people, indian people, etc. those future people would probably think "wow, thats so cool! all those different colors of people! it must have been so exciting to live back then. they really must have appreciated such diversity!!"

(I still dont think mixed breeding is wrong, however. again, it just comes down to priorty - marrying and mating with the person you want, even if theyre a differnt race - or - looking thousands and thousands of years into the future to preserve the different races)