Look, sometimes there are situations where no course of action is perfect. You then have to choose the 'best' course, which sometimes gives some people the short end of the stick.
It sucks, but it happens.
You should probably consider being more precise with your comments. What you are appear to be advocating in general is a situation that has been long recognized by the courts as "marriage confers paternity". IOW, if you're married and your wife has a child by another man, tough sh!t Sherlock. In that sense, I don't think many would disagree with you - the marriage contract trumps biological paternity.
However, outside of marriage, it serves no societal interest to aid & abet any mothers' fraudulent behavior. The situation MeanWestTexan described is by no means an anonomoly.
It's amazing that in this day and age, with the amount of information available on the 'Net & Tom Leykis, et al, on the radio, that any male would be so stupid as to voluntarily sign-up for indentured servitude. In that sense, I'm with you: if you are that stupid, then you deserve everything you get...including looking at a noose to end your misery.