I've heard the same arguments. Sadly, I have no good answer for how the TSA should do their job. However, treating someone rudely and, to an extent, inhumanly, doesn't fit the bill.
In America, things are different. Sure the borders are porous; sure there is a low probability that the muslim guy down the street is a terrorist, sure there is a possibility that the war of 1812 could be repeated by the Canadians.
However, is the country really going to live its life based on insignificant probabilities? It has been 12+ years since 9/11. Surely, there is a time limit after which this insanity can mellow down.
Shouldn't we be "profiling" based on assessed risk? And isn't the NSA making those assessments? It should be a simple as submitting the user's identity and circumstances and getting a guided response back: "no likely threat", "detain immediately", etc.
Not that I'm a fan of the NSA, but isn't that what they are ostensibly there for?