That's just the way the media business works. News. Entertainment. Newsertainment. PBS. They are all in the business of publishing/airing what they think we will want to consume. Of course, when we don't approve of what they are broadcasting, we separate ourselves from the intended audience with the term those people. Because we aren't those people, we have higher standards. It is they who are in control of the content who truly decide what we can read, view, and hear.
With Twitter, though, we have no one to blame but ourselves. Twitter is media without the control of business. It is still open for business, and corporate entities definitely can influence which way the twind blows. But they can't control it.
A look at Twitter's trending topics at the moment reveals a widespread interest in Michael Jackson and Iran and a quiz about what McFLY song you might be.
One could argue that those trends represent three distinct groups of people, but one would be wrong. There is plenty of overlap in those trends. If you follow enough people on Twitter, you'll see plenty of people who tweet both the frivolous and the serious. You'll also see people filling their tweets with nothing but trending topic references and a spam link.
Those people. :)
It's not perfect. But I love that there is this global sampling of people and their interests that is governed almost exclusively by the interest of the audience itself and not just some big-wig's greedy interpretation of it.