> There is clearly room for close cooperation in many areas without surrendering sovereign control over your nation.
Are you sure you voted remain? This is basically the prototypical pro-leave argument.
Given the argument for undoing Brexit is that the EU is "just a trade agreement" and not worthy of any discussions on democracy and sovereignty, I'm always surprised that so many Europeans, even high-level politicians, seem to have taken the decision to leave in such an incredibly personal way. Even the leave campaign itself was squarely against the EU as an institution, not a judgment on the EU member states and the people who make them up.
The mistake I see here is that you are saying "The argument" and "is" implying that there is a singular argument/factor/opinion in play. This kind of simplification is not the way forward.