Haters gonna hate.
As annoying as somebody slowing a security line down can be, hating on them for not traveling at lot is silly.
We're all a fish out of water somewhere. For as slick as some might be in airports, I'm sure there is someplace where you are just the most annoying inconvenient waste of time to somebody else. Maybe even to these crappy travelers.
Though that said, there is never an excuse for crappy parenting. Shut your damn 9 year old.