In the end, all discussion about social standards and policies is a discuss about rights and justice. There are philosophical tools for that: veil of ignorance and the original position.

Usually socialists favor a high degree of collective cooperation, while libertarians favor mutual beneficial cooperation. The problem with the former is to establish consensus about what is acceptable and what not, while the later opens up the door for exploitation, since two partner never have the same bargaining position.

With respect to tax this means that libertarians perceive the state as a third party which doesn't contribute to any two-party agreement. Thus the state is not entitled to benefits.

The reason why socialist societies exists, is that pure libertarianism usually leads to very unjust societies, with powerful individuals and a lot of exploitation.