You can believe whatever you want to believe. Why, there are even people who think Libertarianism is a practical proposition, and compared to them you are incredibly grounded and down-to-earth.
I believe in realpolitik. Literally in acceptingly the world as it is and getting the best deal possible. That is the EU, for us. What we have done is put up trading barriers to our nearest and most important trading partners. That has already cut 4% off GDP. It will cut another 4% off next year, and the year after that, and the year after that. This is not an abstract thing that doesn't matter. It means a smaller cake to share out. Think the rich will accept a smaller share, even in proportion? No chance! If anything, they will want more. So the people you care most about lose out.
We are not getting socialism any time soon. There is no appetite for it. But even if we could turn public opinion around to, say, 60% socialist, we know from experience that 'socialism in one country' does not work.
I would settle for being like Denmark. That's as much socialism as I want. And Denmark is in the EU which proves such a country can exist therein.