Open carry is allowed in 44 states (soon to be 45). Although admittedly a few of those states you need a license which is impossible to get for the average bear (like Maryland). But the majority of those 45 states it isn't. No license is required at all in 30.
The WaPo writers are idiots.
I am confident that soon Florida will allow OC. South Carolina would probably have OC now if the last OC bill didn't allow unlicensed OC which made state LEOs freak out (which was the correct way to write the bill).