Still, having to do that greatly reduces the problem. The average person who wants to censor a politician they hate isn't going to spend money to buy an account.

Another potential mitigation might be to put a limit on the number of posts that a single user can flag in a day. At some point, the cost of large-scale content manipulation could be made to exceed the expected gains.

It may even be profitable for Facebook to crack down on this. Every celebrity post that gets illegitimately taken down has potential for showing ads to millions of people.