I think it depends on the subject. From my experience, history is an enormous amount of work because of the reading, as it should be. Few contact hours doesn't necessarily mean much work as most of that's in the prep. For others, like languages, it depends. You get much less work for cultural modules than you do in other humanities subjects and, if your language is already at a decent level, the actual language classes are a joke.
I think what a lot of people mean, however, when they say it's too much work is that it's a different kind of work to what they're used to. In school, we consider 'contact time' - ie classes - as the time you spend learning. Homework's just an added bit that you don't always see the point of. At uni, prep is the main thing that takes up your time and should feed into your seminars, as opposed to your classes feeding into h/w at school.