Unnecessary and unfortunate tone. But I have come to expect that...
It doesn't matter that he believed there was an intruder.. Why?
Indeed the State was unable to prove that his intruder story was not reasonably possibly true. Masipa established this fact in her judgment.
However, although she acknowledged he held a genuine belief there was an intruder and was acting in fear, her judgment was inconclusive whether or not she legally justified his PPD claim as a complete defense. (Fear alone does not justify an unlawful killing.)
Masipa also had the problem of Oscar's alternate defense of never intending to shoot at the intruder in self-defense. She ultimately decided for him that must have intended to shoot, but then confusingly said he could not have intended to kill (the deceased) because he thought she was in the bedroom.
It was downhill for her judicial logic from there and no one could say for certain she had found his PPD claim fully justified as a result of her poorly written judgment.
And so she left the door open for the SCA to make their own determination that based on his own testimony it was unreasonable for him to possibly believe anyone was attacking him or that an attack was imminent that would have provoked the use of lethal force under those circumstances.
The State was able to prove that he acted with reckless disregard toward the person behind the toilet door, and would have foreseen that death could likely result from firing four times into such a small toilet cubicle. They were also able to prove that he had knowledge of the unlawfulness of using lethal force under those circumstances.
In summary, his PPD claim was only accepted to the extent that he may have held a genuine belief that an intruder had entered his house and this would understandably cause him to be fearful.
However, it is not just what he thought or believed that matters-- his subsequent actions exceeded the bounds of a lawful self-defense and consequently he was not entitled to the full protection of the laws of self-defense. That is what is meant when people say his PPD claim was "not made out."