I have shoes that I know always beep on the airport scanners, so if I choose to wear them I know it might take longer or I might have to embarrassingly take them off and put them on the tray. Or I can not wear them.
Yes, in an ideal world we should all travel without all the security theatre, but that's not the world we live in, I can't change the way airports work, but I can wear clothes that make it faster, I can put my liquids in a clear bag, I can have bags that make it easy to take out electronics, etc. Those things I can control.
But people can't change their skin color, name, or passport (well, not easily), and those are also all things you can get held up in airports for.
