With respect, I think you're accepting an unreasonably low standard of conduct on behalf of the TSA. Why
should you just accept "random" searches because of dark skin or arabic sounding name? (Even if 90% of terrorists are arabs, which isn't true, but even if it were, that still means that only 0.0001% of arabs are terrorists, which makes the whole racial profiling strategy not only bad morals, but also but operations). More importantly, what would happen if you asserted your rights, even to the smallest degree? What if you asked for an explanation of procedures before they're being performed, would the agents then qualify you as "aggressive"? What if you refused some procedures and asked to leave? What if you asked to call your lawyer?
I also have an arabic-sounding last name (though I'm white as a snowflake, and ironically jewish), and I also have to go through "random" searches on occasion (I had four incidents like this in the airport in Israel). Yes, the agents are polite to me, but I don't do very much to assert my rights, mostly because I feel like it would be picking the wrong battle. However, I don't have the confidence that they'd remain polite and professional if I did assert my rights, and many, many people have the same trepidations when they go through border security.
When a U.S. citizen has to feel trepidation upon entering his country when he's done absolutely nothing wrong, there's something very wrong with our system. (At the very least, I'd expect them to post procedures for public scrutiny and allow going through the regular court system when something goes wrong; as of now the whole thing of "being in limbo" just seems completely backwards)