Now here is where things get tricky (we'll keep it to two main points):
1) Systemic issues exist.
Systems exist; roads, power grids, delivery services, food production and distribution, education, etc. Where systems exist, they benefit some more than others, and may even benefit some at the expense of others. Irrespective of the good intent of individuals within that system, the system itself is constructed in such a way as to promote the welfare of some, and not others (this can be intentional or unintentional).
Examples abound. Historically disenfranchised communities are the typical sites for social malcontents and environmental pollutants; we put our industry and waste-water treatment, prisons and half-way houses, in poor and marginalized neighborhoods. Our system for choosing how zoning laws will be put into effect is set up to give certain people control, and inhibit others from entering the process.
The Libertarian position assumes that all individuals start at the same place, have the same opportunities and live in the same world. But we are each embedded into the systems of our society at different points, and that necessarily shapes what is possible for individuals to accomplish, irrespective of their drive, work ethic, and innate ability.
2) Communal responsibility is necessary to form responsible individuals.
Individuals are a social project! Individuals within our society are put together by their interactions with other individuals, groups, systems, and their environment. Individuals are formed by the relationships they have with parents, teachers, neighbors, coaches, and peers. Individuals are formed by their experiences in classrooms, on teams, in the playground, and in family units. Individuals are formed by the educational system, the political system, and our infrastructure. Individuals are formed by the physical world around them.
All of these factors shape an individual. They do not predetermine the course of his/her life, but they do direct it. The individual still has a will with which to respond to the world, but the world provides significant limits as to what is possible and what isn't. Our unique cultural paradigms helps us to make sense of the world, but they also limit what is possible.
A woman who works hard, graduates college, earns a good salary, and is a faithful wife and loving mother, owes a serious debt to society. She was shown the value of hard work, told she could go to college, given the tools to succeed in school, taught the value of family solidarity, and was born with the ability to pursue these things. She did none of these things herself. Only one thing was hers, the diligent pursuit of what was taught her. For her diligence she should be commended, but she stands on many shoulders.
A man who lives on disability, abuses drugs and alcohol, and fathers children with many women without concerning himself with their upbringing is owed a serious debt by society. We taught him the value of free money and self-destructive pleasure, we raised him in a social setting that was fractured and violent, and we never let him suspect that there was any other way to exist. (I know, I know, you are pulling your hair out at this point. But ask yourself, is it possible that this person learned to do this without being shown how? I know, I know, YOU didn't do it... but then, thats kinda my point.)