He's providing a realistic outcome based on compromise.
Even if the UK and EU went to the table as equals (which they aren't) there would have to compromise and we know what the EU believes in the most.
Which in the long run may be the best course of action for the EU as it is an existential threat.
It isn't killing a state, it would simply be not extending the UK any discretionary courtesy. After all we would be the ones invoking Article 50.
Yes its showing the other countries if you dare leave we will do this to you, its a dictatorship.