I think LFL's issue is that Prowse writes "David Prowse is Darth Vader", not just "David Prowse".
The article also says Prowse is not to do ANY photo events with the 501st Legion. That is so horribly sad. I need to touch base with my 501st friends to see if they've heard anything about that. I wonder how long until he's scrubbed from the 501st's website.
God, how I wish Star Wars were in the public domain.