Neither did Giuliani, but he got more votes. If Hunter had gotten more votes than Giuliani, he'd be in for the same reason as Paul (the media isn't going to leave Giuliani out because he's too well established as a significant candidate; therefore, they can't exclude anybody who got more votes than him in Iowa without looking ridiculous).
"Candidates had to meet at least one of three criteria: place first through fourth in Iowa, poll 5 percent or higher in one of the last four major New Hampshire surveys, or poll 5 percent or higher in one of the last four major national surveys."
Paul and Giuliani get in because they meet one (or more) of the criteria. Hunter doesn't, so he's out. It's not subjective.