I am a human. A humanitarian. A loving husband. A loving father. I "give" for those reasons. BTW, my wife (a generous woman) feels the same way.
Both of you are saints then, (or getting pretty close to it!).
Those of us who do expect something back for loving our children you must find pretty despicable, though there may be cause for you to consider just how other's minds might work.
I chose to have a child, (she was planned, and her mother was my then wife). Both of us loved our child, and I'd suggest our love for our partners had something to do with the reasons why we were able to show the love we did, (I believe it was for me anyhow, and I doubt I could have loved anyone else's child in the same way, or even another child by a different mother perhaps, as I only ever wanted one child).
Why should I say I expect something back, (ironically I dont get anything at all back, but that's s different story for a different thread)?
It seems to me the reasons why most parents choose to have children are because of our own needs. Maybe our need to be loved, certainly a drive to pass our genes on comes into it, (though the urge to do so probably sits in our subconscious somewhere). Therefore most if not all, had some selfish interest in having children I'd suggest, (you're exempt of course from any thought you did anything for your own benefit). I used to think I would give my right arm for my daughter if it would help her, so some level of commitment there you might agree, so why do I think she's wrong not acknowledging me or allowing me contact with her? Well, to the age of twelve she might tell me she hated me, followed by "Keep coming daddy", and this I did of course, and I put aside all the stupid obstacles placed in my way by my ex., etc.
If you want to encourage parents, particularly fathers to try to look after their children post divorce (or separation from the other parent), I dont think telling them they should be saints and expect nothing in return will work. Even those of us who did succeed in seeing our child for ten or so years regularly cannot try to convince those men/dads to put their life and emotions into their child, "because it is one of the most wonderful experiences you can have", when it is doomed to failure, partly because we are not supported by those in authority who, like you, consider parents should not expect anything back.
Does that help you see another side to this?