While it's true that Chinese culture tends to serve food more family style, you can eat individual portions with chopsticks and family style with a knife and fork.

The more likely explanation is that in areas where cooking fuel was rare, cutting meat up before cooking it saves a LOT of fuel, and chopsticks, which are easy to make (you just need two sticks of roughly the same side) became effective eating tools. Then it became a cultural tradition.

I do agree everyone should learn to eat with them, too. It's handy, especially if you are interacting with people from those cultures who find it respectful for you to honor their table etiquette.