I recently realized that M-D-Y makes a lot more sense than we give it credit for. Date formats needn't be about the cardinality of the units, in this case it's about spoken language. The M-D-Y format simply follows the order of the words in (EDIT: American) English. We say January 4th, 1970. Try reading D-M-Y in (EDIT: American) English and you will quickly realize that it doesn't make sense. I suspect most other spoken languages use 4th January, 1970 so D-M-Y feels more natural to them.
EDIT: I'm sorry if I offended you by equating American English with English. Point taken. I misspoke. The point remains.
EDIT: I'm sorry if I offended you by equating American English with English. Point taken. I misspoke. The point remains.