Not a bad idea. If they’re funding the Daesh, a violent death is entirely appropriate.
Shouldn’t be drones, though. unless the targets are already in a failed state like Yemen, Syria, Libya, etc. False flag assassinations are better, as are apparent “workplace accidents.” The real problem will be dealing with state actors. Killing Saudi royals will be really embarrassing all ‘round.
If they have managed to get a lot of the “civilized” world behind them, then I doubt there is any mortal power that can do anything about it any more.