Pessimism is not realism. Getting the full verbal support of a second-term lame-duck administration with nothing to lose is not a negligible achievement. Some progress != no progress. You're right that petitions have limited scope and effect, but in successful efforts like these, they can generate publicity and political momentum, giving ammunition and gravitas to Congressmen who would co-sponsor legislation. At the very least it is a step in the right direction.
The system is broken, but sitting back and needlessly berating those who would try to take small steps to achieve small goals is hardly an acceptable response. It's calculus; if you integrate a positive attitude over a large enough population of believers, you can effect large-scale change. If you integrate so-called "cynical realism" over the same intelligent population, you create a self-fulfilling prophecy of defeatism which is nothing to pat yourself on the back about, either. I applaud sinak's achievement and I hope that this conversation shifts to what steps need to be taken next.