Kind of an amendment to Robert's answer, which I agree with: if it's something that's not going to get closed outside of intervention, and it needs to be closed, please flag it.
However, if you have a good reason to flag something instead of voting yourself, do not flag as
doesn't belong here →
<close reason>. Use a general moderator flag and explain the situation. This is for two reasons. First, because it's a better way to explain why you're bothering to flag rather than just vote. Second, when you hit 3000 reputation, flagging something as
doesn't belong here will convert your flag into a close vote, thus not alerting the moderators as you intend to.