Lets say all the non-mining full nodes reject the block. Why would the miners care? the miners are the one creating the blockchain. You can cry foul all day long but unless you can vote with your hashpower on which chain is correct, you are yelling to the wind.
Miners care because the businesses that accept Bitcoin run full nodes. Businesses will choose to run the nodes that the users are using otherwise they would not have any other customers and would thus be making no money from accepting a different chain. If no one accepts the miner's chain, then they are mining something has no value. Bitcoin is not ruled by miners.