You have load from different directions. The hulls depth isn a seaway is different, the wind is moving around, and the boat is turning. The loads are not static or even.

If you are snow skiing is the load the same on each ski or part of a ski as you turn? On a flat surface, straight down a fault line, and if you carefully distribute your weight evenly.

The boat is going through equivalent of double fault mogul fields sometimes. To make it more different, the rudders are (except when one is free wheeling) the rudders are at the same "attitude". So, like a four wheel drive, you have different loads each time you turn.