Japan may be full of single men, and I'm sure many are wonderful people, but she already failed once in her judgment, so how can she trust herself not do to it again? Is it laziness to avoid swimming after you've almost drowned before?
Plus, you're actually reinforcing her position, by treating "a father" as something you just go out and get, like a car. What if she simply doesn't want to be intimate with anyone? How many single men are prepared to be a father without being a husband?
What you're essentially saying is that you agree that she should hire a father for her daughter, only that she should pay with her body instead of her money.
I think that's harsh and short sighted. Why is marrying a single man better for her daughter? How is that more "real"? It's certainly not true in all cases. If her mother remarried to an abusive alcoholic do you seriously think that's better than hiring what's essentially a professional father?
In every social interaction we can never really be certain of the other person's motivations or feelings about us, or even if they really have feelings as opposed to being an automaton or a hallucination. In many cases it doesn't really matter that much. When a waiter smiles and laughs with us, they might just be thinking about their tip and how much their shoes hurt, but we can still enjoy their company.
Parenthood, romantic love, close friendship are not like this. They rely on a deep level of trust. If you pretended to be my lover, it wouldn't be enough to say "well you couldn't tell and you enjoyed it". There is an implicit shared emotional connection.
In particular, children need to be able to trust their parents.
Children who have been adopted are also "tricked" but I don't think all of them prefer their birth families.
The comment above is implying that the woman is "a lazy, dishonest bitch" for not going and finding a boyfriend or husband so that the girl won't be bullied at school, which is a pretty clueless thing to say. The idea that a family needs a father in order to have any worth or be treated with any respect is the cause of the problem in the first place, and this comment is just reinforcing that ignorant and incorrect position.
In other words, the reason the woman needs to hire someone in the first place to keep her daughter safe is because of people like the person who posted that comment.
There's a well documented reason why there are a lot of single men in Japan.
What is that reason? (Serious question)
The reasons behind _that_ aren't so well understood but generally seem to be disillusionment with the idea of falling in love, getting married and having a family, unwillingness to fit in with traditional expectations (housewife taking care of the kids + hard working salaryman husband) or simply seeing relationships as too hard.