Greetings friends. I'm late to the party, and didn't read all of the comments above, but skimmed most of them. Forgive me if I repeat anything. I'm captain of a very similar ship, and work for the same company. I have pilotage for the river in question. I've been making that turn for more than 15 years.
That turn is one of the most technically demanding turns in the lower rivers. The channel is narrow, and the current is strong. It is generally not less than 2.5 miles per hour, and can exceed 4 depending on conditions. The area is so treacherous that all of the industrial docks that used to line the river there had to close due to all of the collisions. This section of the river is now one-way only for larger vessels, and is closely monitored by a Vessel Traffic Service.
The current is strongest in the outside of the turn, as it usually is in rivers. When piloting a ship upbound through this area, it's important to NEVER let your ship reach out too wide in this turn. The stronger current on the outside of the turn will catch your bow, and affect it disproportionately more than your stern, causing your rate of turn to decrease. It can be very difficult to get her turning again, and you don't have a lot of time to waste. If you don't get her turned in time, the current will set your ship hard to the west, and you will very likely hit the wall, causing catastrophic damage. There have been many large shipwrecks here due to this.
When you see the freighter turning to the right to avoid the sailboat, he is doing the right thing. He is working toward the part of the river that he can navigate most safely. The current is the slowest here, putting it at the least risk. Turning to the left would have been very dangerous.
These ships don't turn on a dime, and it takes time to make up your mind in a situation like this. Slowing down wouldn't have done anything but reduce the freighter's maneuverability. There very likely wasn't a call made on the radio, as there would have been very little time for it to have been useful.
I don't subscribe to the 'tonnage law' necessarily, and I WILL move out of the way when the rules say I should, as long as I can safely do so.
Contrary to what many people think, the average captain isn't an idiot or an *******, and genuinely doesn't want to make the news, damage anyone's property, or god forbid hurt anyone. We're just trying to move rocks from one place to another, so we can collect a paycheck and go home. We're not out here to 'scare sailboats.' When I see people making broad judgmental comments like 'the captain should be arrested' it makes my blood boil. I try really hard to ignore that kind of thing, but boy, it makes me want to say something that would disagree with my signature line.