In their own misguided way, I understand the logic behind the attack on Sony. When a company "declares war" on hackers, they should be prepared for the inevitable backlash.
What I don't understand is the attacks on all of the other companies. Given, they may not be related, and may simply be all happening around the same time by coincidence. But (for example) attacking the Bethesda site because they think Bethesda didn't give the public enough new Skyrim details during E3 is just absurd and childish.
It reminds me of that Twilight Zone episode about the kid that could alter reality. If you give a group of irresponsible egomaniacs too much power, they give you no choice but to destroy them, or spend the rest of your life in fear.