Why not just disintegrate everyone and say they were displaced into the past? That's about like kicking someone in the groin to "relieve" their suffering from a toothache.
Last but not least—and this is the biggie—this is just throwaway fiction meant to entertain people for an hour. It is not hard science unraveling the mysteries of the universe. We needn't rationalize an explanation, as it already has one. It's just TV, dealing in catharsis.
Oh, very true...but sometimes I'll watch this stuff and ponder the stories regardless. It's a fun way to exercise the futility muscles.
There's just so much inherent weirdness in this episode, it begs questions. From the time travel of perhaps billions (just how long would that have taken, anyway? And apparently there's only one portal?!), to the Atoz replicas (who perform the "simple tasks"). Has Atoz been doing this since childhood? And he also says that "he thought everyone had long since gone", so why is
he still there? And Maurice is right when he asks why Atoz would wait until the very end to go himself, according to my theory. Unless deep down he hates his wife and family or something.
Then there's Zor Kahn, the tyrant of whom Spock "learned about from reading library records" when he did no such thing. And why send Zarabeth back in time as punishment for "choosing her kinsman unwisely". Who hasn't done that at one time or another? Her crime is vague and seemingly minor, yet here she is painted as a kind of female Lokai or something. never diid get that.
As for why McCoy didn't revert, I guess humans have always been reasonable and well-balanced.
Good work, guys!