Do you think some people are turned off by the Byzantine and undemocratic structure of the European Union? It advertises itself as being not an actual government, yet acts like it. An imperial order in bureaucratic dress.
There's no prime minister or cabinet responsible to the European Parliament the way it is in most EU countries. From what I can tell it's hard to tell who's "in charge" at any given moment. In this sense it's not democratically accountable. Whatever exaggerations and oversimplifications there may have been during the runup to the 2016 referendum, or however simplistic the minds of the voters may have been, or who they are, one wonders if those who accuse it of being not democratically accountable don't have a point.