If Musclepharm truly did anything underhanded as far as NSF labels go, NSF would have removed all of their products from their site and would have issued a warning or revocation.
NSF announced back in March they were looking into allegations of false labels. It's now June. Guess it wasn't some major illegal scandal as someone is trying to make it seem.
Edit: didn't know about the NSF letter till just right now. Ignore above.