If you spend time in central Europe you'll see why this occurs. Some people have incorporated the EU institutions into their personal identity. People will call themselves European Citizens although the EU doesn't grant citizenship. Businesses will be called Euro-this or Euro-that for no obvious reason. You can catch the Eurobus to go ride the rollercoasters at the Europa Park then meet their famous mascot Ed Euromouse. This stuff is everywhere.

And in some ways, it is understandable. The 20th century was wracked by wars between different European empires or countries. The assumption at the core of this movement is that if everyone has the same social identity and is ruled by the same government, then everyone will hold hands and there will be peace on Earth. Or at least that bit of it.

But you can't force unity on people. It has to develop naturally, through shared experiences and cultures. Unfortunately the vision is so enticing that the political and credentialed classes in these countries don't want to wait, and so attempt to enforce it from the top down via schemes that eliminate democracy in favor of power transfers towards the Right Sort Of People, the type who "get it" and who can then rule unchecked without needing to answer to electorates. This is deeply corrupting, but because it's an identity issue when this is pointed out people feel their personal identity and whole progress story is under attack.

If you look around you see plenty of people that gets upvoted and are critical of EU, so that isn't it.