Non-interference is a good default position to have, but we are capable of acting on behalf of others when we have a certain threshold of confidence for what they would want in a situation. Otherwise, we would consider it wrong to give CPR to an unconscious person.

When it comes to life, people overwhelmingly prefer to continue existing when they have the power to choose. So it makes sense for us to presume that a hypothetical person would choose to be born given the opportunity.