The police only investigate serious crimes or imminent threats where either a lot of money or someone's life is on the line, and even then, they aren't fast, accurate, or trustworthy. The legal system does not have the time or the motivation or the resources to deal with what is the online equivalent of schoolyard antics.
That is not to say what these idiots were doing was trivial or harmless. But let's put it this way: suppose every time you had someone come up to you and say something completely disgusting and violent to your face, that your response was to do absolutely NOTHING except file a police report, do you really think that would stop such behavior? If someone punched you, are you just going to stand there and not defend yourself, instead electing to wait until you can go to the nearest station and file a report?
The bottom line is that you cannot reasonably expect to have a free internet while at the same time tell the government or law enforcement that users must be held accountable for their online actions. People suggesting that victims simply shrug off such behavior are either themselves psychopaths or have never themselves been the target of such abuse. And to then call out the victim for vigilantism is the height of delusion. Oh, but what if this opens up a slippery slope of unchecked vigilantism and real-world consequences for people who are the mistaken subject of retaliation?
Um,... I have some news for you: it's already lawless out there. It has always been. You can't simultaneously tell people to shrug off the trolls because "oh well that's the internet for you," yet cry foul when people fight back, saying "but what if innocent people lose their jobs?" That's hypocrisy. People are already suffering real-world consequences of the behaviors of trolls. You are just selectively inured to it because it happens a LOT more often and it's been going on for a lot longer than people successfully fighting back...and when they do fight back, it goes viral and makes the news because so many people are so desperate for a solution that it feels good to see the good guy winning for once.
That should tell you how completely nonexistent civility is in the online realm. People SHOULD be accountable for their actions online. But don't fucking tell me that it's the job of the government to do that for me, because we all know how PERFECTLY that works. What a joke. Accountability is not actually kicking someone in the balls for being a jackass. It's being able to carry out the promise of that consequence.