I think it's an exaggeration to say that "justice prevailed". Those ones should have been happy to have got off lightly. Seriously, do you think there was even one among them never involved with at least one murder? In my opinion, it would have been much better if they resisted arrest, giving the cops an excuse to gun them down. It's one thing to say they were "formally" clean, it's another to seriously call "justice" a case where some of the biggest scumbags in the country walked free. It's a good thing anyway the meeting was raided, who knows what they would have decided there had they been allowed to finish: any time organized crime's plans are somehow stopped (even temporarily), it's a good thing.
Really, using a case of mass arrest of crime bosses as an example of malfunctioning of the civil rights system doesn't make sense to me. It's possible lives have been saved by that raid, or at least death sentences that could have been emitted by the bosses during the meeting were held over temporary, since the mobsters had to be busy with their legal defense for a certain time after that.