These airport checks are not intended to filter out abortion clinic bombers, the lunatic Tim McVeighs and Ted Kaczynskis of the world. They were instituted as a direct result of 9/11 and the threats of further attacks from Al Queda and affiliated groups who want to attack the US. Tim McVeigh has nothing to do with that.
I'm not saying racial profiling is necessarily the way to go. I have a problem with it, just as you do. But at the same time, you still need to profile. Serial killers are traditionally profiled as middle-aged white males. It's a profile based upon previous cases and psychological assessments. How is this different? Yes, you still want to investigate the 20-something Asian guy if you have reason to do so, but you still initially focus on the people who fit the profile.