I don’t think this premise is as intuitive. For example, if someone said that a quadriplegic should have saved a nearby drowning child, then the objective appears immediately this it wouldn’t have been possible and so the “should” claim isn’t reasonable. On the other hand, if you say that the quadriplegic should avoid intentionally drowning the child, I don’t think that’s clearly nonsensical or false.
I don’t think this premise is as intuitive. For example, if someone said that a quadriplegic should have saved a nearby drowning child, then the objective appears immediately this it wouldn’t have been possible and so the “should” claim isn’t reasonable. On the other hand, if you say that the quadriplegic should avoid intentionally drowning the child, I don’t think that’s clearly nonsensical or false.