People make mistakes due their enviornment and genetics (capaticity to learn and whatnot). Libertarianism is absurd when there isn't even freedom as we know it.
Everything is absurd if you think of it that way. It is perhaps a valid logical point, but it is not constructive. So what do you suggest, delegation of all (illusory) freedoms to other, bigger and stronger organisations because freedom is an illusion anyway, so better to just get rid of it altogether?
Oppressive systems can still cause suffering whether or not people have true 'free will', and even a deterministic mind can define it's own mistakes, and learning from those mistakes is still possible.