I can't see in Simon's comments a underlying message and criticism , if he doesn't like an act he just says it (his way), he did it to the Mc Donald Brothers (back in 2006, he was horrible , makes Louis look an angel) where there was constructive criticism at all. Anyway it's a show at the end of the day, they only want to keep their own acts so they'll say anything which in some cases play as a tactic imo
The only thing wrong with Joe's second performance was the nondescript shirt they had him wearing - I'm not saying that he should have dressed up like Elton John, but surely something better could have been found for him.