That's correct, but I'm not the one criticizing the activists without more information. You, however, are more than happy to reflexively condemn Israel. Although I'm waiting for more information before rendering any judgment, I will say that the Israeli side of the story seems a lot more plausible to me than the crew's side of the story. Let's compare:
Side A: Israel stops six ships heading into Gaza, per their normal procedure. Five stop and are searched by Israel without incident. The sixth refuses to stop because it contained weapons, and is forcibly boarded. The crew, knowing that the weapons would be seized, decided to defend them with force. Israel then returned fire.
Side B: Israel stops six ships heading into Gaza, per their normal procedure. Five stop and are searched by Israel without incident. The sixth refuses to stop out of "principle" even though it didn't have any weapons, and is forcibly boarded. Israel opens fire on this particular crew for no reason whatsoever, even though they stop ships hundreds of times every day. The crew then defended themselves against the "attack" with, umm, weapons.
and if you don't see the obvious aggression in boarding a boat on international waters with guns, then your either blind or purposefully deceiving yourself.
There was a blockade in place. The crew knew this ahead of time; it's not like this was highly out of the ordinary and they didn't anticipate it. If they CHOSE to run the blockade and then fight back when Israel boarded, then it is their fault.