And by that statement, it seems obvious that you haven't seen the TNG episode in question. . . or you associate "military" with "evil". . .
In "Yesterday's Enterprise", characters remain essentially the same, except that the timelines have diverged at the point where the Enterprise-C either stayed and saved the Klingon vessels (thus leading to Fed/Klingon peace) or fell into the time rift, thus not saving the Klingons. . . and leading to a long Fed vs Klingon war that did not go well for the Federation.
But, in that alternate timeline nobody who was evil becomes good, and nobody who was good becomes evil.
Though one that was dead became live.
...
Seriously, I think Tasha Yar set a record for most appearances of a dead character.
It diverged before first contact. Dr. Flox compared diffrent versions of famous literature and was saying the "real" universe versions were all full of weak pansies, except for Shakespeare.