Gaza Protests: Did Israel Use Excessive Force?

I don't understand the Israel / Palestine situation. But my initial reaction seems to be at odds with that of just about everyone else--which, of course, means that I'm probably wrong. But it seems to me that force is justified if people try to storm your border en masse--even if they're unarmed.
   Anyway, here's a very generic thing from the BBC suggesting that it's at least a somewhat open question.