Earlier quoted context omitted.
There's less of a feedback loop there - people don't know if their submissions have been flagged or not.
On behalf of authors everywhere, please don't use the flag button as a downvote button. This, for several reasons: 1. It's overpowered. Based on some experiments I conducted a year or so ago, it seems like 1-2 flags equal about 10-20 places dropped in the rankings. It's brutal. A single person in a bad mood can drop a story like a stone. I don't know the exact maths, but a single flag seems to have the effect of many…
Disagreeing with something is not a reason to downvote either.