I think you're mischaracterizing the situation.
Perspective 1: UK is breaking up with the EU, not vice-versa.
P2: EU gets some adv/dis-advantages by including UK specifically P3: UK had some advantages/disadvantages from being part of EU P4: EU has incentive outside of British sitch to stay unified
My (american) perspective is that Britain should stay in the EU because while their direct adv to leave may outweigh direct disadv to stay, they are subject to P4, which is to make an example of someone who leaves.
Exclude your judgement of right, wrong, and what should be. Look simply at leverage.
When France decided to leave the previous union of European states, the #remain folks definitely inflicted a lot of short term pain. Lots of French beaches still have monuments thanking the British, American and Canadian soldiers who died in support of #leave. Did that short term pain make #leave the wrong choice?
Also, as a Yank, I'd just like to tell any Brits on here that we still love them. Think about joining NAFTA. Our wine is just as good as French wine and London needs more burritos. We'd love to have some curries and all your delicious baked goods.
Also, the UK has negotiated many concessions over the years, including the rebate, various exemptions and vetos including from the ever-closer union and the euro. So a less good deal as the result of a total renegotiation we initiated is not so much a punishment as a reflection of the reality of the prior concessions.
There is of course realpolitik in the desire to ensure we have a less good deal and are seen to suffer by other countries to discourage other leaves, but I think that will come naturally from the factors above anyway.
You can call this sort of vindictiveness "realpolitik" and try to sound sophisticated, but this hardly invalidates my abusive ex-husband analogy.
A is true
A is likely to cause B
C is also true
C is likely to cause B
If B occurs, it is incorrect to blame only C
where A is the current exceptions made for the UK, B is a fairer deal (fairer to the other countries, which will be worse for the UK by definition) and C is your abusive ex-husband part.And you're still comparing a mutual union of countries for their mutual and collective benefit to the Nazis?
And the pain GB will experience post-leave is due to not having access of benefits a treaty granted them. The leave folk believe that's fine, and it'll be a long-term benefit. That's arguable, but leaving that aside: The short-term pain is entirely self-inflicted.
Blaming that on the EU is a rather staggering amount of cognitive dissonance.
It's right in the contract that member states have the freedom to leave.
So tl;dr; Britain should stay in the EU because #remain folks want to start a trade war with them to punish them for leaving? And that maybe this will result in an actual hot war? You seem to be doubling down on my abusive spouse metaphor.
I'm a huge free trader and open borders type. (And also a yank in India, so no skin in the game.) But listening to the arguments of #remain folks makes me think the UK is better off on their own. With friends like these, who needs enemies?