Now, now, Onhell, there are better reasons to criticize that "performance". First and foremost, the lack of a guitar solo. Second, the incorrectly played bassline. But the t-shirt? Appetite For Destruction is a great t-shirt.
However, I should note that my criticisms above should be taken with a grain of salt. For all I know, these guys have only been playing for a few months and that's the best they can do. ... Well, that still doesn't excuse the bassist trying to play the guitar part. But you know what I mean. It may be unfair to hold these two to the standards of highly-talented musicians, because they apparently are not. But we all have to start somewhere, and these guys may get better with time.