This is not the case. The Seidenberg and McClelland paper itself does not report what rate of correct reading of nonwords the model can achieve.
People are very accurate at reading aloud pronounceable nonwords.
As I've already mentioned, the PDP model is not accurate at reading nonwords aloud, so cannot explain why people are. So the PDP model cannot explain why people are so accurate at lexical decision. These attempts have not succeeded. This is phonological dyslexia. The dual-route explanation would be that there was abolition of the nonlexical route and sparing of the lexical route.