Of course a couple of complaints are not going to alter radio programming. However, you have to remember Des Moines is a mid level market at best. Complaints to the station as well as to the sponsors, if in large numbers, will have an impact on how programming is handled. That is the quintessential element of "free market" (i.e., the consumers are the ones influencing the business practice).
Furthermore, your comparison to Rush Limbaugh is flawed. I can virtually guarantee you that his sponsors and the stations on which his program is broadcast get a lot of positive feedback as well. Hence, the shield of protection he has from those who complain. A small market guy like this Perrault (sp?) doesn't have the cache to overcome a barrage of complaints to his bosses and sponsors.
I don't have the inclination to any such thing for this particular issue, but I applaud those who take the time and effort to let their opinions be known to those who matter. If it gets results, then the free market is working.