Why can't they learn to be sensitive when certain characteristics like that come up occasionally, especially since they aren't really a predictor of being a thr

Why can't they learn to be sensitive when certain characteristics like that come up occasionally, especially since they aren't really a predictor of being a threat? You might as well say "the TSA's job is to be alert for abnormalities, so unfortunately it's inevitable that if you wear polka-dotted socks then you're more likely to be pulled aside for additional screening." It doesn't have anything to do with anything.