In the scope of the world, the universe, our existence won't have mattered. But, the interactions and connections we make in each of our lives is vitally important. For better or worse, we matter in the lives of our fellow humans.
Understand that the events of one's life shapes their perception of the world. While you might not share a point of view, their opinions are inevitably the result of the sum of their experiences.
Society is made better by the exchange of ideas. But to forcibly compel a person to adopt your ideas as their own removes the benefits wrought by discourse. It is the journey to knowledge that brings personal and societal growth.
Doing so is tantamount to exercising mastery over another person. There are times though when it is necessary to charge a fee for expertise; such a free should always be at most commensurate to the benefit that would result after sharing.
This goes beyond slavery. This would include manipulation as well. To rob a person of his/her free will is the same as robbing him/her of his/her humanity.
Nature is the larger community to which we are all members. We need not revere nature as superior to ourselves, but we ought to strive toward treating nature with dignity. To exhaust nature would be to condemn our descendants.
Essentially, we are a mechanism to help advance entropy; strictly speaking, propagating and producing descendant generations is the duty of lifeforms. But, living life is also to say that we must seek out experiences and immerse ourselves in the human condition.
This is the Law of Karma. Every action has an equal and opposite reaction. But the reaction may not always be be felt immediately. We are makers of our own destiny.
There was a time called the dark ages where ideas and progress were held back because of religion. That still happens. It also happened because of economic and political reasons. That still happens. Key battle ground of mistrust and poor psychology.
Each living entity deserves to be treated with consideration, care, kindness. It's what helps bring life satisfaction to the one being kind and joy to the one being treated kindly.
All ideas are subject to critical dissection and future correction. New evidence must always be allowed for and factored into our thinking. To hold onto any idea as unquestionable/unchallengeable is a form of bigotry.