I always wonder why people think musicians and artists should work free? Did you ever hear anyone ask a plumber if they would fix their sink as a labor of love? I wish my dentist would fix my crown pro bono because he is talented and enjoys sharing his gift with the world. I doubt if any one of us would show up to work for free. If you do, I have could use a new roof and my kitchen cabinets need replaced.
Pete Seeger is not a dilettante and it would be rude to expect someone of his stature to show up and share for nothing. Same as any musician. Pete is a very generous man, and he has given freely of his time and money. I think the question was probably asked innocently, but it is not the first time I've heard people question musicians fees.