There is plenty of alternative here. People have the largest soap box in the entire history of mankind to speak their grievances from: the internet. All of the tools are in the box if you want things to change. The difficulty will always be rallying people to a banner, figuratively speaking.
Outlaws are set apart from vigilantes in some respects, as the definition of outlaw is significantly more broad. An outlaw can be something as innocent and simple as a character like Jean Valjean in Les Miserables... they can also be people that heist banks at gunpoint.
The point with vigilantism, in the history of mankind, it has achieved little. They tend to be isolated acts that effect no real change, and usually cause a visceral and vicious response that negates the efforts of the people that aren't vigilantes. Every modern change has either been through revolution or through change from within. Even then revolution is fraught with danger and rarely succeeds producing something better.
If you want a good look, check out the middle east.. Particularly Egypt. They had a revolution, threw an old dictator out leaving a power vacuum for potentially a larger threat to fill in. This of course being the Muslim Brotherhood the antecedents of modern terrorism. Another example is the burgeoning secular government in Tunisia. It's already at threat from fundamentalist Islamic sects wanting Sharia established in both civil and criminal capacities with the state left to handling usury. I know this sounds like a line from Fox News. But, it is not in any way bullshit or something to be discarded as an object lesson.
The reason why civil rights and women's suffrage were seen through to success were tireless efforts to change the system from within.
When sane men turn to outlaw justice, when remedy is available within the system either through what's established or changed by uproar... It's a dark day and is insane after a fashion.
Sony isn't the core problem here, they are acting in what they view as their own best interest. It seems a bit stupid to the rest of us, but that is their right. It's also our right to look broader and bigger. As a movement, I think patent reform and intellectual property law to be changed is going to be an uphill battle for years. This requires more than a DDOS. It requires spokesmen, money and time.
If anything has been proved in self government, money as a motivator for change in political systems has been the most successful route. So anyone getting pissed off about this shit, should go donate money to a centralized effort be it the EFF or something new. If they can, donate their time. Hell go sit down with your state legislators one by one and explain the issues. Outside of our geek community nobody gets why this is a bad thing. Education is needed more than anything else. IP law for dummies.
So when everyone decides to use that soapbox, with one voice... that will be the day shit starts changing.