...I agree with your assessment of the TSA's usefulness... and like you believe folks deserve courtesy (until proven otherwise..)
I too have never had a problem with TSA staff... funny thing is, I am NOT a uniformed airline employee.....never have been.
I don't doubt the bad experiences some folks here speak of.... but I haven't experienced such things myself... ever.. and as I travel routinely with firearms I deal with TSO's more often than the average joe....
It isn't just the security screening for me...it's baggage check in too...