The probability of any hijacker being of any other ethnic background other than Middle Eastern is zero.

That just is not true. Any security arrangements that were based on that kind of assumption would be suicidal. Even if it turns out that what happened on Tuesday was Middle East related, that wouldn't in itself mean that all those involved would have been of Middle Eastern origin.

And in any case, there's the copy-cat principle - people from elsewhere with grievances, screwed up individuals. Including home grown Americans like Timothy McVeigh. They all know now that aeroplanes are potential flying suicide bombs.

As for freedom - sure, it affects freedom, having to worry about being targetted and taking precautions, but that's not what it's about. When Bin Laden and company were fighting the Russians they weren't the least interested in whether they were democratic or whatever.