First thing that comes to mind is the play, "Tartuffee", which mocked hypocritical priests who preached the holy bible but sinned in private and were secretly corrupt. Controversal subjects, like this, could have profound impacts on society and bring attention to these taboo subjects. Although at the time of release they didn't preform too often, it's now recognized as a major work and contains valid criticism. This isn't to say there isn't limitation over what should be talked about, but at the very least it's impossible to ignore the positive impact it had on society as well.