As in most cases like this, the real question has not been mentioned in the article. There are only two questions.
1. Did he commit the crime, not beyond a reasonable doubt, but since the death penalty is involved — absolute certainty? Answer, yes.
2. Are people safe from him: in prison, if he escapes, or is paroled? Answer, I don’t know.
Always remember the McDuff case. If people are not safe, that is the time for the death penalty. Nothing in the article indicates that was even discussed. I don’t even know if the law permits it to be discussed.
However, point #2 is up to the judgement of the jury. At that point, all kinds of life lessons, stereotypes, prejudices and whims come into play. Only one juror in the article even mentioned a threat to other inmates.
In my opinion, none of the points in the article are relevant here except that they distracted the jury from discussing point #2.
So, should the Supreme Court have ordered a new punishment phase? Probably so, but not for the reasons presented.