I don't think the jury appreciates the defense focusing on irrelevant information. During the jury selection the potential jurors were asked whether they could consider mitigating factors during the sentencing phase. I think the potential jurors were hesitant to agree to consider age, sexual abuse etc in deciding whether life in prison or death would be more appropriate. What makes the defense think that the jury is going to consider those factors during the guilt or innocence phase? I think they are annoyed that valuable time is being wasted. They just want the facts.