It's okay in that it is a free country and you can say what you want. It isn't okay if leaving the kids' table is something he ever wants to do. Joining adulthood requires putting on big boy pants and unfortunately I think it is too late for Mr. Nugent to ever achieve such faculty.
Personally I don't mind him saying it. To me, such uncouth utterances are akin to holding up a giant sign saying, "I have nothing interesting, useful, or intelligent to say, so don't waste any time on me." I value my time so am always appreciative of such signage.
The bigger problem is that he represents, unfortunately, the juvenility of far too many people in this country. It is unfortunate in a broad sense, because conservatives could (and should) have important contributions to make. There are all sorts of legitimate criticisms to be levied against Obama, just as there are legitimate concerns about the size, scope, and role of government, but we don't get any such cogent narrative from the GOP, instead we get name-calling, invent-a-scandals, and daily beatdowns of the make-believe socialist, Muslim, Kenyan, antichrist, lizard-person Obama who exists only in their imaginations.
It is a tragedy really, and I can only hope someone in the GOP eventually retakes the adult table and puts the kids back in their place, but I don't really see it happening. I suspect 2016 will roll around and the GOP will still be grilling Clinton about the Benghazi scandal that has never existed while she coasts to an easy victory and conservatives will keep on lamenting that liberals simply refuse to see the truth (of course, 'truth' being an imagined truth that has no actual objective evidence).