Sailor Moon only reacted in that way to a monster attack. And only in the first episode. Luna and Artemis are from another world. It's not a mystery.

In Star Trek Voyager one of the Q actually denied that the Q were omnipotent. Anyway it's definitely OOC for Jean-Luc.

Why don't Luna and Artemis just tell them where they're from?

I think you meant why is there some sort of mystery. You're right, though.

As before, why is there sort of mystery about Luna and Artemis? They're not from Earth.

The reason for the objections to saying that Q is omnipotent-which, in the one episode where a Starfleet officer called them that, one of the Q said that they were not- was because Captain Picard said it. Which, of course, he never did. It's also true that Serena only reacted like that in her first episode, and it was a reaction to danger, not to being in a strange place.

It's called Mau.

Luna and Artemis are both from another world. Simple as that.

Neither was Rubeus, for that matter. He, Pluto, and the Black Moon are all from the second series, not the first.

Sailor Pluto isn't in Sailor Moon until the second series.

A pet dragon? Are you referring to Jupiter Thunder Dragon, which is just a name?

Regarding Serena breaking down in tears-she did do that-IN HER FIRST EPISODE.
No mention of Luna and Artemis being from another world?

Apart from the errors regarding Sailor Moon, didn't Captain Picard refuse to believe that Q was omnipotent?

Also it was a reaction to something very different to arriving on the Enterprise.

I know she did cry often but she only reacted like that, saying "I want to go home" in the first episode.