As Bob points out, it’s because the people in the media are:

It’s no wonder why people are confused about this stuff. When the so-called very serious “experts” have no flipping clue what they’re talking about, it makes it very difficult for their viewers to get it. And it’s not like Mr. Five Million Dollar Annual Salary can’t afford a staffer to print out the Wikipedia entry for single-payer.

Bob is talking about Chris Matthews, who apparently doesn’t know the difference between single payer and the public option. I have trouble believing Matthews doesn’t actually know the difference. I have a sneaking suspicion that there is something more to it.