When I decline a flag, it is sort of a pain, because I have to click
Decline and then select or write up a reason as to why I declined it.
This makes sense, I fully support that, even though it's a pain.
However: Don't make ♦ moderators select a decline reason on Community's flags. Community flags a LOT of stuff, some is useful, some is not. So why should we have to explain ourselves to a roving bot?
Also: Registered users (anyone who doesn't have a diamond or works for Stack Exchange), can NOT see Community's flagging history, so it doesn't even help, if users wanted to look at that and see why we declined a particular flag of Community's.
In short, let us decline flags from Community without having to explain why.