Some people are unhappy about the ending to Mass Effect 3, some people are unhappy about Mass Effect 3 full stop. It's difficult to judge each complaint individually and fairly when the people shouting the loudest sound so immature, but supporters of the petition "Retake Mass Effect 3" may have found a decent way to raise awareness for their cause without sounding like four year olds.
For a start, they've managed to raise $30,000 for charity Child's Play – that doesn't sound too much like the work of entitled children. That's obviously exactly what they're going for, but whether they really wanted to make a difference or whether somebody thought it'd just give their cause a little more weight, the result is still the same and that's worth supporting.
Mass Effect 3 as a whole has had quite a bit of controversy surrounding it; this is the first example of something good coming out of it. Whether the cause actually makes sense, I can't say, but it seems there's enough people out there who believe it does that Bioware may even be looking at their DLC schedule again.