The EU-related structures in Brussels are about as united/fragmented as the US Congress, indeed.

But the national governments are nothing like US state governments. A lot more political fragmentation, plus they still consider themselves executives of sovereign nations with various vital interests and also historic resentments. Few Californian politicians will base their programs on suspicions towards New Mexico. In Poland, "don't kowtow to the Germans" is still a living idea and current PM Tusk is regularly accused of doing precisely that.