First, I think that the ban is well diserved. Grosjean is simply too reckless in the first laps, the stats says it all, somebody needed to give him some time to reflect and maybe look at the starts from the sidelines, learn something
Second, I completely agree with everybody that Malfunctionado (copyright Hail22 via ballg2k) is way past such a penalty too. I certainly hope that next time he does causes a crash he will get one of these too.
Third, in my opinion, looking at the video, Grosjean knew very well where Lewis was. Because otherwise why does his car stops moving right within a few centimeters of Lewis's front wheel? Coincidence? I am not a big believer in these things

Also it seems to me that Grosjean moved so fast to the right, that Hamilton could have braked only exactly when he saw Grosjean moving towards him, otherwise it would have been too late. And if all drivers would brake when they see a car moving towards them... well... I guess we wouldn't like that kind of racing would we? And then, when Grosjean interlocked the front wheel of Hamilton is almost a crash waiting to happen (unless by some magic they make it into the corner with their wheels perfectly interlocked

).