So it seems ass if we have two separate complaints about the PBS special:

1) The performers were all (or almost all) pop-folk acts rather than "real" folksingers.

and 2) They shouldn't call that stuff "Folk Music".

As much as it may be painful for the hardcore folkies to admit it, that early-sixties pop-folk was extremely popular, and an entirely valid genre for a nostalgia show. While dropping a Doc Watson or Tom Paxton into that crowd would have made as much sense as putting the Julliard Quartet into a Lawrence Welk special. It's just not what that audience wants to hear in that context.

So what do you call it? The people they wanted to reach think of that stuff as the "folk music" of their youth. Those people are ignorant cretins by our standards perhaps, but they're ignorant cretins who send money to public TV.