As much as possible, closing of questions should be done by the community in general contributing one closevote each, rather than diamond moderators using their closehammers. (When I say "closehammers", I'm talking about the privilege given to diamond moderators, not to gold badge holders - I don't think I've ever seen a gold badge user mark a question as a duplicate)
The community is frequently prepared to close questions, so I don't think the following argument, made in the early months of Skeptics.SE apply any more:
Time for the community to decide...
That means closing questions that need to be closed. This is happening; it needs to happen more.
The main circumstances I'd see using a closehammer as appropriate is in the following circumstances:
- A question is so problematic (at least in its current form) that the community would almost certainly close the question if given the opportunity.
- (Possibly) a question hasn't received enough eyeballs to determine whether or not it should be closed.
- Acting in response to a non-3K user who has bothered to raise a flag about a question.
- The community as a whole has somehow got things badly wrong, and is ignoring policy possibly because emotions or biases have affected the thinking of the community.
The case of Was there a negative response to the video of Alexandria Ocasio-Cortez dancing? , where a diamond moderator closed the question, it was re-opened by the community pretty swiftly, and then was closed by one 3K user and one diamond moderator, indicates that something has gone wrong, either with the community or the diamond moderators.
It's even more concerning when moderators also delete (not even moving to chat) a bunch of comments addressing whether or not the question is on-topic, at least one of which was highly upvoted.
In fairness to diamond moderators, they don't have the ability to cast an "ordinary" closevote, and sometimes wait until four closevotes have been cast so that they have the same amount of power as ordinary closevoters.