Because he will get off easy. Here's what would be the PERFECT end to his life
Life in prison in SOLITARY CONFINEMENT. No contact with the outside world. No tweeting. No TV. No radio
Just books. Millions of books. No nothing else. Until he dies. However long that would be I don't care. He could live to be 100 or die at 80. I don't care. While he lives he would be deprived of the spotlight. Deprived of being the center of attention. Deprived of having anyone anywhere hear anything he had to say. Wouldn't that be way loads lots better than putting him out of his misery ASAP?