In "Prime Factors", Janeway was angry but did not explicitly say she would demote the two main conspirators, Torres and Tuvok. Yet a few episodes later, both of them have one-half pip less on their collars. Well, so does Tom Paris, who never did anything wrong in "Prime Factors" - but he's Tom Paris, and obviously had it coming.
(In reality, all three had it coming for a long time; the writers were having second thoughts about the ranks of these characters and felt that the dynamic would be better served with lower ranks. With Torres, it was easy, because her murky Maquis insignia were so difficult to read; at times, they appeared to feature two bright slashes for full Lieutenant, at other times one bright and one black for Junior Lieutenant, and in "Faces" even two black slashes! With Paris, one clearly bright pip had to go dark. Only with Tuvok did they actually have to remove a pip, though, the dark or "half" one.)
The fun thing is, if we assume Janeway did demote Tuvok, then it follows she never ever promoted anybody during their years of exile. She merely restored the ranks of those she had previously demoted, first Tuvok and much later Paris. We could then argue she felt she had no authority to actually dish out permanent promotions without being in communication with Headquarters - so she didn't personally hate Harry Kim's guts, she merely was a stickler to her own rules...
Timo Saloniemi