How effective do you think stripping away the rights of Arab-Americans will be? How hard do you think it is for terrorists to find a generically white-looking fanatic to commit terrorist acts with? And what happens when someone like Timothy McVeigh decides he wants to use a plane this time, instead of a Ryder truck? As some others have pointed out on various boards, profiling based on race is lazy investigation.
There are plenty of methods that would be far more effective: have competent baggage screeners at airports, have air marshals on flights, profile based on clear risk factors such as where, when, and how the ticket was purchased, whether the ticket was one-way, etc. etc. Clearly, I don't have all the answers, but that's not what they pay me the big bucks for.
But how about I ask you something? When you say we should "err on the side of caution," how far to that side must we err? Do we give white passengers the right to kick off any Arab-looking passengers they don't like? Because that's been happening. Do we ban all Arab passengers from flying? Because that's been suggested. Do we force Arab-Americans (even US citizens) to carry special identification like the Nazis forced the Jews to wear special stars? Because apparently 49% of Americans think we should. When you say that discrimination and prejudice are justified, where do you stop? At what point does our disrespect for other people's rights disgust even the most bigoted of us?
The ultimate question is this: you mention that if someone decides that you and people like you are a threat, you'd be willing to be inconvenienced. But why is it that when Timothy McVeigh blew up the building in OKC, no one thought white males should be profiled? No one suggested white males be barred from renting Ryder trucks? No one suggested white males ought to have special identification? I'm not necessarily looking for an answer -- but it's something to think about, isn't it?