I think what Stacie L says is right on the money.
But, assuming you're quoting the result literally, I'd also ask,
Are we to believe this result encompasses the whole world?
How many people outside the US were included in the USA Today/Gallup poll?
Absent that information, the claim should probably be " According to the results of a domestic US poll, where total respondent numbers are clearly not sufficient to equate to a representative standard of world opinion, Barack Obama and Hilary Clinton were rated the most admired man and woman alive - in the USA."
It should probably also have a rider saying, 'Selected from a preset list of nominees prepared by USA Today Editors and Gallup Poll research strategists"
Finally, (sorry to go on, I just hate seeing all this pseudo-research posing as truth), I haven't seen the poll, and won't be wasting time looking, but unless either of the two achieved a vote above 50% of the total ratings, it would be more honest to say, 'Barack Obama and Hilary Clinton were rated least un-admired.'
Poll results are like statistics. Fodder for spin merchants.
Winston Churchill understood how powerfully manipulative statistics can be, when he rated them in sequence, "Lies. Damn lies. And statistics"