It doesn't need to be wrong - democratising violence mean people with boats are more likely to have weapons and ability to attack you. Or the ability to disrupt trade, for that matter.
Coast-hugging boats can be made from wood with some skill. Weapons in that era requires metal in some part. That required a lot of skill.
This isn’t what the Sea Peoples built. It isn’t even what the Romans built. Most Mediterranean cultures lacked the navigational and ship-building expertise to let the shore out of sight. That doesn’t mean they didn’t need skill. But it was less skill than needed for metallurgy, in part because the latter’s inputs are dearer.
Making a boat that can carry multiple people on sea without sinking when the weather goes a little sour (which can happen in less than an hour in the Mediterranean) is a very hard thing to do. And if you know how to do that you'll never have any shortage of metal or other goods in the first place because you end up being the one who trade them for profit.