The booing that followed his name being called out was aimed at Arshavin.
Or even if it was aimed at Wenger's decision to put Arshavin on, it was still an idiotic and unhelpful reaction and you could see Arshavin's reaction to it. It destroyed any chance of a decent performance from him. Recently I think Arshavin's been working a lot harder. He's desperately lacking confidence but his workrate has been pretty decent. Booing when his name is called out isn't going to help.