In all seriousness, a Chinese coworker of mine actually once asked me about this custom about Jews eating Chinese food on Xmas/New Years. I smiled, then replied that we Jews eat anything exotic (e.g. Chinese, Middle Eastern, etc.) when we find an excuse to 🙂
For the record, there is no set law where we HAVE to eat Chinese food. It’s just something that’s done where we decide to simply “eat out.” No rhyme or reason.