I still don’t understand how a socialist can pretend that the EU is in some way progressive — it is a global neo-liberal driver like the IMF and the ECB that has brought Greek society to its knees and imposed austerity even harder on countries like Ireland.
The EU is not like a government that happens to have a neo-liberal government — it has neo-liberalism written into its constitution and its statutes. It is not possible to pursue consistently socialist policies and remain a member of the EU.
If Britain was to reverse its decision then that would be a massive victory for the EU leaders, Macron and Merkel especially, who would proceed further with forcing its member states further down the road of economic liberalism. But so would remaining members of the single market, which means accepting its competition and labour laws.
We should argue to guarantee the rights of all EU citizens in the UK but oppose accepting any right wing EU restrictions on UK law.