"Peace is the founding principle of the EU" - Jason Hunter in his Project Fear speech.
"In truth, Brussels is a democracy-free zone" - Janis Varoufakis
https://www.theguardian.com/politics...at-theresa-may
"EU doesn't do democracy" - Seph
The core of the economic argument is that the UK is so deeply integrated with the EU at the practical level that leaving on WTO terms will severely knock us back.
The core of the democratic argument is that the UK should be sovereign and free from the EU's shackles (to the extent they exist - which is where there is debate).
The piggy in the middle is the Irish border and the EU are playing that n order to undemocratically shackle us to the Customs Union and split the UK into two.
In these circumstances, sovereignty trumps economics and we should take the hit if it comes and build from there.