Because he is perfectly capable, but is lazy. To give you an example he will happily feed himself a yoghurt but nothing else with a spoon. He will eat his sister's and our food but will not feed himself a meal with his hands.
We've tried sitting him at a table with his sister, I've even tried putting it on a plate next to me on the sofa to see if he goes for it but he knows!
He is only 15m so I know he is still youngish, but this is frustrating. If he isn't napping during a 'snack' window I will give him some finger food which he generally accepts and eats no problem but he isn't a massive snacker.
Anyone else gone through this?