oh for goodness sake, 'deserve her kid' is shorthand for 'deserving of the responsibility to maintain custody of her child' ie. being worthy, meriting or, as you put it, 'being up to the task'. there's no need to be intentionally obtuse.

Sure, obviously. But if you meant "she's an idiot who doesn't deserve her kid" why frame it in a disingenuous question and then spend multiple posts sorta semi saying it in not so many words. It is after all, your right, to have that opinion, just as its my right to say that "she's an idiot who doesn't deserve her…

If you are truly asking why people do things that are a bad idea or that they'll likely do poorly, the answer is that its the HUMAN CONDITION in a FREE SOCIETY throughout time and place.