The same way as a "Mirror Universe," in which good is bad, bad is good, and the ship flies right to left instead of left to right.
Which was nothing of the sort. It was simply an alternate history in which the civilization was more violent and barbaric. But there was still the capacity for goodness there, as seen in Spock and Marlena, and the Halkans were just as pacifistic in both universes, so clearly it wasn't some silly cartoony inversion of all things. And "left" and "right" are arbitrary designations in space -- either prograde or retrograde orbit is physically possible, and since orbit is an unpowered trajectory, there was no instance shown of a spacecraft travelling opposite its own direction of thrust.
I'm not saying any of it made sense -- in any of these shows. I'm just saying that they're all FUN. It wasn't until TNG that we all got so worried in knowing every last scientific reason on-screen. How much techno-babble do you want in a half-hour cartoon?
You're missing the point. The point isn't that things weren't explained -- the point is that they couldn't
be explained, that they blatantly could not happen as depicted. There is a profound difference between those two notions. I could write a scene in which a superstrong alien cyborg survives a fall off a 50-story building and it would make sense even if I didn't explain the specifics of the technology that allowed it to survive. But if I wrote a scene in which a glass sculpture survived a fall off a 50-story building without any damage at all, that's not just unexplained, it's clearly impossible and self-contradictory.
There is no requirement that a story explain everything. But it is obligatory that a story, even one in a fantasy universe, be consistent with itself
. That its own internal rules are coherent even if they are invented rules. And the way the inversion of time was depicted in "Counter-Clock" was self-contradictory on multiple levels. It doesn't hold together even by its own rules. And that is always a flawed way to tell a story.