As the refrain goes, it's not clear exactly what went on when Israeli commandos boarded convoy of aid ships, starting a confrontation in which 10 people were killed (though none of the commandos). Probably the Israeli military knows what happened, provided their troops aren't incompetent or covering up. It might take a wikileaks-style full-length video to give everyone else the chance to make up their minds. I think what I've written here is appropriate to most of the likely events, but it could be invalidated by an extreme truth, from either 'side' of the debate.
Whatever their motivations and whether or not they were foolhardy, I can't help admiring the bravery of those who resisted the boarding action. You're transporting a cargo of aid to Gaza, making a political statement against the blockade. You know the Israeli military is out to stop you. You're going to challenge just how far they will go to stop you. As long as you're in international waters the legalities are, to say the least, disputed.
When they board you in the middle of the night, you know they're going to, at the least, hijack your ship and detain you. If you want to stop them it comes down to a matter of force. And as any freighter captain sailing off the horn of Africa will tell you, the best way to repel boarders is as soon as possible. Catapults and whatever weapons you can improvise versus machine guns. These people must have known what to expect in a fight; expected the Israeli commandos to respond with deadly force.
They weren't attacking civilians and they weren't blowing up soldiers from afar. They were fighting face-to-face with soldiers trying to board their ship in international waters. Unprepared soldiers, perhaps, but still fully-armed soldiers.
I think the fundamental Israel's 'bungling' is making this basic miscalculation - they expected people to back down when faced with superior force and deadly violence. Instead they found people unafraid to fight back against the odds.
I can't shake the feeling it's like a strangely inverted Cuban Missile Crisis, with a catastrophic loss of moral and political standing instead of a nuclear war as the consequence of intercepting the ships.