[R U Ready?]

I think he is being genuine but he does of course have a history (as does Creed) of using feuds to write songs and it could be inspirations for his songs like Reach Out, Fight Song, and Hard Way. It could be sarcasm b/c the feud ended up having come to the place to write a solo album or he could just be thanking them and realizing whre his career originated and why he's famous in the first place.