No, not almost certainly - certainly! At least they will certainly owe tax.
He's not talking about they will owe tax, despite not having any withheld.
Americans aren't allowed to hold on to their own money and then cough up the taxes on April 15th. If you somehow fail to have enough withheld from your paycheck, you will have a penalty fee on top of your regular tax that you have to pay.
Oddly enough, you also have such a fee if you set yourself up for excessive withholding, and thus a very large refund.
None of which has jack to do with the perceived, so-called "medal tax."
So, to summarize:
Moron attention-hungry reporter or blogger discovers that the IRS takes a share of the medal-winner's prize money and calls it a tax on the medal.
Uninformed public finishes their Chik-Fil-A sandwiches and rallies behind a cry of "Unfair!!! Abolish!"
Informed entities like snopes.com and myself point out that the withholding is just a normal withholding of income tax from money received by the medal-winner. Everybody pays income tax on their earnings, and that's all
this is.
More uninformed persons misunderstand and join the "Unfair!!!! Abolish!!!" bandwagon, probably posting on their phones from Chick-Fil-A.
Kids not old enough to know the rules of taxes post up with "Wait. Whut?"