undo the devastating effects of 40 years of lies and hypocrisy (mostly by the Tories, but Labour, especially Jimmy Corbyn, isn't free from blame) regarding the European project.
We also have to see Merz's statement in the context of domestic policies: His party is, under his leadership, heavily turning towards neoliberal politics. The UK has always been the home of such policies in the EU (favouring big business, cutting down on social programs).