Imagine this
Japan
Canada
USA
India
China
Would they choose to sign up, as they are now, to:
Free movement with trade partners.
Trade partners making most of their laws.
Governed by the unelected not in their country.
Currency union with trade partner(s) where there economy will be calibrated to much more trade within this union, and less ability to make other relationships.
A plan for a single military and foreign policy and flag with this(these) trade partner(s).
Referendums where the constitution is not accepted ignored or held again until 'right' result
Threatened with economic punishment if they leave and try and be sovereign and make their own relationships.
Would they join?
Would the whole of their political class and media call people stupid and racist for not doing so?
Would they conduct their national debate based on what all the largest banks and corporates, plus what all other nations leaders wanted, not their own populace, whom would be addressed with sneering condescension for opposing?
Look at the aforementioned objectively, and in a historical context.
This is the behaviour of a country that has abandoned solidarity and the national interests.
It is the behaviour of a governing class of a semi-colonized nation being prepared for takeover, who believe the 'natives' are hopeless.
It is the behaviour of those who equate independence with racism, either stupidly or deliberately falsely- as it has been labouriously pointed out(mainly to fall on deaf ears) we are the most mixed and diverse country in Europe.
Homogenization with Europe would have decreased the proportion of ethnic variation and mixing,(and especially integration-as did too higher immigration levels, [militantly promoted by the politics of the last 20yrs; neoliberalism, in my view] which reversed our previous success in this area) not to mention spiritual and intellectual traditions.
This in favour of a narrower Caucasian-Christian culture, plus of course the disastrous problem with Islamic militancy.