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I can see that as a necessary reason to have it 🙂. It's difficult for people not to abuse it when they can apply it with great force against a community member who might be saying something offensive or what-have-you. You're gonna find people who say stuff that you believe is complete quackery, while I might not believe a lot of it, let em say it if they don't have it on 24/7 repeat.

You're thinking of flagging, downvotes can have more reasons.

I do not see a separate button for flags and downvotes. They are one and the same thing, AFAIK.