Because why the fuck would they? Who the fuck do you represent?
If you put a border in the Irish Sea, you lose the DUP and the government's going to collapse.
This problem has no solution. You're not going to solve it with a Pooterish Brexit in your little lunchtime.
They haven't got the votes. They can't get Brexit through and they can't survive without it.
Welcome to planet earth. Now grow the fuck up.