I have seen this playacting win in a couple of other cases — the Menendez brothers and the Lorena Bobitt trial. All they did was cry during their testimony. Even though the Menedez brothers shot their parents gangland style at close range, pumping their bodies with many bullets, they were let go because they said that their father molested and abused them. They could not deny that they killed them so they switched to a “innocent by victim-hood” defense. And it worked.
I think people identify with the people involved in the trials and they judge them based on whether they like them or dislike them, whether they remind them of a mean father or someone else that they may have liked of disliked.
I watched the Menendez case pretty closely. I think Lyle was the lead sociopath and Eric the dumbcluck follower.
The police suspected them from the start. Sociopaths always think they are so much smarter than the rest of us. Eventually it's their arrogance that does them in.