What is this -- a slam at birth fathers?

In the New York Times, there's an op-ed by James Collins, where he claims to be Mark Zuckerberg's birth father and asks for money.  What is this?  A slam at Steve Jobs' birth father? At birth fathers more generally? A juvenile attempt at humor with no particular point?  And what exactly is funny about the stereotype of birth fathers as not interested in parenting unless there's money in it for them? Take a look and tell me what you think:

DEAR Mark,

I have learned from the reports surrounding the death of Steve Jobs, at much too young an age, that he was adopted and that while he knew the identity of his real dad, the two never met. This has saddened me, and I feel that I can no longer justify denying you that same opportunity.

Mark, I have some news that will come as a shock: Edward and Karen Zuckerberg, two wonderful people, are your adoptive parents, and I, Jim Collins, am your biological father.
I can imagine your surprise! It’s not every day that a 27-year-old learns that he was adopted, much less a 27-year-old who, according to Forbes, using the August sale of Facebook shares by Interpublic as a basis for valuation, was worth $17.5 billion as of September 2011!

I want you to know at the outset that in no way do I wish to force a relationship on you. You already have a “father,” in the sense that he provided you shelter and basically adequate nutrition while you were growing up, if not in the sense that you are his authentic, natural child. And while it’s true that the doctors are saying that without a heart-lung-liver transplant I have only a few months to live, I would never want to ask you for anything. I am here, that’s all I want you to know. But — just to say — if you were of a mind to help, making the check out to “Cash” would probably save us hassle on both ends.

So, I confess, I just don't get the point. Can someone explain it to me?