"Flagging" on Steemit is a misnomer, on the database/blockchain level there's no actual "flag" like you would see on any other website featuring a function named that. On the blockchain it's a negatively weighted vote, or for short: a downvote.
The concept of flag is unfortunately a hack that has been stubbornly retained on the steemit.com front end.
I've removed my downvote from this post but cannot remove the downvotes from other posts because of their post age.