How long ago was it that the last public hanging took place in the US? There was a time when these were done in the town square, for all to watch. Did they check ID to see who was old enough to see the show?
How about the last lynching? Some of these were pretty public affairs, and I don't think they kept kids away.
Just off the top of my head I would guess that there were public lynchings into the 1950s and maybe even later.
My point is that less than 50 years ago the US engaged in much the same behavior.
It does not make the spectacle correct social behavior. I believe that executions should be publicised, but not compulsory for citizen personal attendance. Other than the judge and jury. The judge and jury must be compelled to attend in the event of a death penalty IMHO. I have served on a jury that involved a capitol crime.