I call it reverse profiling. They singled you out to show that they're not always hassling kids and minorities at the mall. So they find an old white guy to bother that they can point to later and say "see, I bother old white dudes too".
I get the same thing at the airport. I know before I even put my carry on bag on the conveyor belt that I'll be taken to a small room for a pat down and questioning. Old silver haired white guys don't cause problems on planes, but they need to show they don't discriminate.
