I take your points. However, I have to disagree with the idea of using flags to indicate disapproval for a post just because you may think it lowers value - in that case, simply don't vote. The devs have clearly indicated that they want flagging to be treated differently than the downvoting you describe, by calling it flagging, giving it an icon than isn't a down arrow, and by placing the button elsewhere. I think the ergonomic/psychological intention of this is clear - flagging is not intended to be used as the opposite of upvoting, but is to indicate a post that is in contradiction of the community's code.
With regard to your point about bots, following from @dan 's latest announcement on the subject I think we're going to see a lot of improvement on that front anyway, which would lesson any bot-related problems with my proposed solution.
Doing nothing and allowing someone to be rewarded for lowering the value of Steem would be worse than doing my part in stopping it. I have a stake in Steem, and it's in my interest to protect its value.
Sure, I can get behind that. Perhaps then we need a separate system of downvoting. In my opinion, flagging should not be viewed in the same way, and I think the devs agree by making it different in the UI.
Summary of discussion in chat:
gs: Steemit UI matters most
pf: Steem is the meat and potatoes
gs: Steemit UI says flag
pf: Steem is upvote/downvote
gs: Steemit UI is all that matters because most people use it
pf: I use Steem CLI for many votes. You can flag abuse, and I can downvote when I feel it increases the value of Steem. We'll keep our concepts mutually exclusive :)