For the life of me I cannot figure out why his attorneys did not object to this juror. He's had horrible legal advice throughout this process.
AFAIK the general practice in all jurisdictions is that each side can challenge a certain number of potential jurors -- some for cause and (I think) fewer without stating a reason. There is a limit, however -- they can't just go on challenging jurors forever! Maybe they had used their limit.
They ran out of their challanges by the time they got to him. His attorneys did as well as could be expected considering the obvious bias of the judge and outright hostility of the jury.