Because im arguing, "if you support utiliarianism, you should agree that conscription is sometimes necessary".

But you disagree with utiltarianism. You call it "terrible"
So I'm trying to tell you why utilitarianism is valid.

And from the example, if you are going to throw this one guy out of the boat, which I think is the right thing to do, then you believe that more life is more valuable than fewer life.

In that case, i would argue that people's life is valuable because their happiness is valuable.

If you don't want to throw this one guy out of the boat and decide to just drown with everyone, then I would ask you where that value came from. If you say God, or Law or something like that, i would argue that it's a circular logic and cannot be used. because Law is a human invention and often wrong, and God is also a human invention.

did I make myself clear? Now, would you throw this one guy out of the boat or not? Or do you agree with utilitarianism? You clearly did not.