If it was past experience involving a boat, you'd think they'd attack powerboats. I really doubt a sailboat would have likely been involved into hurting orcas to the point where they would have learned to attack sailboats. Sailboats have keels in front of small propellers, and the propellers are usually purposefully not "exposed" or the first thing to be hit when colliding with an underwater object.
On the other hand, power boats have very shallow draft, basically no keel, and much larger and exposed propellers. And yet, it's sailboats that are attacked.
Hence to me it's quite obvious that the orcas are taking on the sailboats because sailboats are easy, slow and vulnerable targets. It's more likely that a bunch of young orcas are being jerks, like teenage humans are to vulnerable people. Also I don't buy that somehow orcas would be this pure, unable to do evil, species that is merely induced to be angry as a whole group because of the big bad humans. If they have a social structure, they have members of society that are jerks.
One way or another it's a problem if they target vulnerable boats.
Not sure if you're familiar with the kea[0], but it's a rather intelligent alpine parrot, and very social, and, like orca, when one learns something new, the knowledge is transferred to its peers quickly.
When I was living in a village in the mountains, groups of young male kea would come down to the village to have fun and incidentally cause trouble.
E.g., one group would hang out by the public toilets, and when people would pull in to use it, the kea gang would deflate a car tyre, sometimes two, it felt like a way of showing how tough they were, because one kea would remove the valve cap, then the other kea (plural) would take turns depressing the valve to make that "pfsssh" noise for as long as they could handle it, then to a chorus of cackles from its peers.
On the other hand, power boats have very shallow draft, basically no keel, and much larger and exposed propellers. And yet, it's sailboats that are attacked.
Hence to me it's quite obvious that the orcas are taking on the sailboats because sailboats are easy, slow and vulnerable targets. It's more likely that a bunch of young orcas are being jerks, like teenage humans are to vulnerable people. Also I don't buy that somehow orcas would be this pure, unable to do evil, species that is merely induced to be angry as a whole group because of the big bad humans. If they have a social structure, they have members of society that are jerks.
One way or another it's a problem if they target vulnerable boats.