1. Talking with parents will only show you how they feel from their perspective, biased by their perception of themselves. Becoming a biological parent doesn't automatically make you an expert on parenting, or even a good parent. Furthermore, we, unfortunately often think of ourselves as better people than we really are. Few of us are capable of honest introspection when it points to our personal flaws.
2. The initial choice to have and raise a kid is often not as selfless as we'd like to believe. The extreme example would be those who have children as a way of trying to hold a relationship together. However, for most folks, people seem to be enamored with the idea of having a 'mini-me', or with the general concept of being a parent. Sometimes getting married and having children is entirely born of societal expectations, even if that compulsion is more subconscious that conscious.
I'm not saying that all, or even most of these people are inherently selfish, that they don't fall in love with the children they bear, aren't good people, or any of that. However, I seriously doubt that the act of baby-making is usually as selfless as what we would like to believe. Personally, I've always wanted to get married and become a father, but considering my financial reality, and many of my flaws as a human being, I feel that procreation would be a deeply selfish decision.
There are many animal behaviors that have no discernible advantage or function, some of which, such as moths flying into flames, are actively detrimental, but are a byproduct of an organism's adaptation, nonetheless. For a more benign example, we can look to dogs humping people's legs. I can't think of recreational sex as an insult to procreational sex anymore than I can consider eating a Big Mac to be an insult to nutritious sustenance.