I don't think it's an option that's really on the table. There's no real way to discern between a flamer who reports a player out of malice (instigating/baiting flame to validate reports) and a flamer who honestly reports another player for breaking the rules.
Additionally, if the IFS did throw out reports on account of the reporting player having flamed/misbehaved, look at it like this: What happens when someone flames an actual troll and then tries to report them?
Granted, flaming trolls accomplishes nothing, and I wholly advise against it, but a fair number of people believe that the troll trolling justifies their flame, and some handful of those players just make the honest mistake of letting their temper go in such bad situations.
So, should their reports be ignored on account of them having misbehaved, too? Letting the troll get off scott free wouldn't do anyone any favors, so, you can probably see how such a system would be counterproductive.