I suspect some of the backlash from people picking unpaid internships has a lot to do with the demographic. Because we know only people of a certain ilk can actually survive those situations, it creates a sense of anger that people who would love to work at those places aren't being given the opportunities because they can't afford. The anger may be directed at the interns but it's most likely just frustration boiling over in general and landing at those who can take advantage of the opportunity.