I saw a moderator active on a question that I thought was off-topic and they did not close it... and it annoyed me. Mods should do the right thing, all the time, every time. Right?
A moderator not closing a question does not mean the question is on topic. If you feel the question is off-topic, vote to close it; it takes 3 votes¤ to close, whether a moderator edited, commented or answered it.
That quote above is something that crossed my mind several times before I became a moderator. Some questions that were obviously off-topic were commented on, edited and (even worse!) answered by a moderator.
That's okay to disagree. Mods votes are unilateral and sometimes we find that a question is borderline, so we don't vote to close. Or we only have time to do a small thing on it and don't have time to properly close it.
But that does not mean that we're always right. So, again, if you think it's off-topic, vote :)
That's the power you, the community, have.
¤ The site is still configured for 5 votes, but I generally close those that have at least three.