It wasn't meant to be a "your guy is worse" comment
although I see how you might think otherwise. To be blunt, George W. Bush is not very articulate. For this, his opponents talk about how stupid he is. On the other hand, when Kerry says something equally inarticulate or indecisive, he's praised for being "nuanced."
There's a reason why no sitting Senator has been elected president since 1960. The public has little interest in or respect for the arcane procedures of the Senate, where "I voted for the $87 billion before I voted against it" is a normal way of doing business.