anything positive which is retained or created as a result of us leaving the EU?
It’s not a symmetrical position though, is it?
In one case, you have somebody who has actively voted to remove something from everybody in the affected population, who then themselves actively sets out to preserve that something for themselves (seeing as citizenship, being the thing in question, can’t be shared out with others).
In the other case, you have people who haven’t actively chosen the outcome which is against their personal preferences, but who will be having to live with the overall consequences because, well, here we all are.