Maybe look at their on-air schedule. The syndicated Ryan Seacrest show is on at that time, so a ton of those spots are national clearance for carrying the show. Also, 11am isn't a heavily listened-to time slot, so stations tend to run barter spots during off-peak hours to satisfy contracts.
Besides, you apparently had enough time to waste to notice that they played 21 minutes of spots that hour, so maybe you were the only one inconvenienced.
Let me ask you this, and please answer seriously: How many years of experience do YOU have working in Radio? In programming, on-air, sales, anything. How many checks have you written for staff, FCC fees, tower maintenance, etc.? Maybe you can look at our point of view and realize that we live in the real world and have to pay for everything YOU, THE LISTENER, get to enjoy for free.