An obvious concern is that plebiscites can be quite intolerant, or that a nation's people's intolerance can be reflected in the laws they choose to approve. Switzerland recently passed a referendum against minarets. But representative parliaments can be intolerant against Muslim minorities. Belgium just outlawed clothing that does not allow one to see a persons face, i. e. full-face niqab and burqa.
(The law does allow people to cover their face if their work requires it, e. g. a welder's mask or a surgeon's mask. And there is a procedure to have police approve masks at certain carnivals. But what about a ski mask against the cold?)
And, of course, the United States has incidents of rendition, internment of the Japanese, and Jim Crow.