but they really mean openness to subsidised exports from the metropole.
Your're confusing free markets with the effects of the Euro.
By incorporating vast but less productive areas of Europe into the same currency the Euro locked in low valuation and accordantly attractive pricing for German exports. Countries like Greece went on a spending spree: cheap goods all round... the government especially took to spending on "Puff projects": massive military spending (gotta show them Turks...) Olympic games (gotta show the World...) but of course they had (corruptly) joined the Euro by lying through their teeth about the state of their finances, and the Euro being half baked had no proper central bank powers because it simply wasn't made to deal with such a situation.