"If the whole world..?" This has been true for decades.
I have worn something with 'Cowboys' practically every time I have gone through airport security. Every time. Every freaking time. One person sees me, diss the Cowboys and it starts like wildfire throughout every security line within eyeshot of me.
The few times I have boarded with gear? I see other NFL fans wearing gear left and right going through security. Crickets except for ONE time I was on the shuttle train between gates at Hartfield International when a couple of Saints and Falcons fans got into it.