The study isn't so much talking down the internet as it is talking down the average person's work ethic. Of course people are going to get defensive. The only person who wouldn't is someone who actually spends a couple hours a day wasting time, is a manager, or isn't working.
And the point being made by many people isn't that the internet is good (which it is), but rather that sometimes its more productive not to be working 100% of your day. This is why some companies put pool tables and basketball nets in the workplace. Its not to lose money, but to "increase productivity".