Why do people talk about single parenthood like it isn't a choice?

People always talk about the "plight of the single mother" as if they were victims or if it was something that wasn't a choice, like being poor or being persecuted because of your race or religion. And if someone tries to explain how lack of fatherhood causes serious problems for children and society, they look at them like they're the antichrist. Why? (A lot of people complain about single parenthood but really don't care about children and social problems, they just want to point fingers, that's not who I'm talking about.)