I think downvoting would require anonymity, and if flagging is to function as downvoting, that anonymity is required there as well, so as to avoid retaliation spirals.
Also, the cream is definitely not rising to the top here. I've found absolute garbage doing quite well, despite being the equivalent of snake oil. That's what inspired this post to begin with, the reality of shit rising.
RE: A question for the Steemit community about the mechanism of downvoting and the dangers of charlatans