I agree with the general sentiment of what you say. However, I can't help but disagree with some of the specifics.

You say that the most selfish motive for forming relationships is sexuality. How can you come to that conclusion? Sexuality is something that is shared by and enjoyed with the other partner. Both partners in a sexual relationship receive pleasure and gratification from the sexual acts. Some couples even go so far as to venture into adult stores together to seek out new ways to spice up their sex life. It is a mutually enjoyed and mutually beneficial act. In fact, it is common to find that one partner receives as much enjoyment from giving pleasure to their partner as they do from receiving it themselves. I am not sure how you are able to come to the conclusion that sexual motives are more selfish than any other.

Neither do I agree with you about the idea that parental relationships are considered altruistic by society. With the exception of those for whom parenthood has come when they were far from ready for it, when someone announces that they are expecting a child, do people express sympathy or greatfulness for the soon to be parent's willingness to take on that sacrifice? No, not at all; the soon to be parent is congratulated and treated as if they are about to receive one of the greatest gifts in life. There is a certain amount of sacrifice that goes with accepting a parental responsibility, but ultimately people do still seek parenthood not because they are willing to endure it for the sake of humanity, but because they have a (selfish) desire to raise children. I don't believe that our society views parenthood as altruistic at all.

Lastly, I wonder how you come to the conclusion that we reinforce a distorted world-view on this forum. What world-view is that and what is it we do to reinforce it?