Yahweh continues telling a parable to Ezekiel about a cooking pot that represents Jerusalem, so rusted that it cannot be cleaned from its rust. The people of Jerusalem cannot be cleaned from their sin. They have been completely rotted. This parable continues through Ezekiel 24:14.
Casting lots was a way of choosing which pieces of meat to take out, but because Yahweh wants to take out all of the pieces of meat, there is no need to cast lots.