Well I'm not suggesting you write something like that! It would be harsh!
You could just say, "The moderating team understands your concerns but we don't agree with this flag at this time"? Or maybe disagreeing with a 'Something else' flag should prompt you to write a response message.
Otherwise from a user point of view they flag the post for 'something else', say "can you please move this post as the start of a new topic", you as a moderator disagree and click 'disagree', then you go off and do other stuff. Meanwhile the person who flagged it gets a message saying, "Thanks for letting us know. We're looking into it" but then no action is taken which prompts them to message you eventually.
Out of interest, is there a way to alter these message templates anywhere in the system if we should want to?