Another reason why Socialist Europeans don't like the EU is that it reduces some forms of socialism like for example Greece has to sell off its national airliner Olympic and privatize it. This may freak out some Americans that assume the EU is the second incarnation of Communism (they are not too well informed). That is why for the most part the French voted no - they want to maintain their form of Socialism.
Another reason people hate the EU is that while it promotes privatization of industries - it also regulates - some would say over regulates industries so it seems as a contradiction - free market that is overly regulated right down to what cheeses are to be called or if cheeses meet the right standard for export, etc.
What Americans in their ignorance call Euro Socialism is in fact what they see as over regulation and over standardization and regimentation.
Americans apparently aren't the only ones so "ignorant". Mikhail Gorbachev has (approvingly) referred to the EU as the "new European Soviet".