banu quraiza

Q: I heard from critics of Islam that, in the seerah, when it comes to the Jewish tribe, Banoo Quraiza, the Prophet (Sallallahu Alayhi Wasallam) checked all the boys if they had pubic hair to determine whether they were mature and baaligh in order to be able to decide whether they should be treated and punished like all the men. Is there any truth to this? Also, were the Bnoo Quraiza judged for their crime by their own scriptures i.e. The Torah or were they appointed an arbitrator among the Sahaaba according to their (Banoo Quraiza's) choice?