Why a Free Society?

Why is a free society where everyone has equal individual rights most preferential?
Because no one possesses inherently more or different rights than others. Stating otherwise is arbitrary. People can only hold more power than others - i.e., more wealth, knowledge/information or force.

Force implies the disregarding of others' individual rights. Wealth implies material assets which can be employed in coercion (and the ownership thereof is not inherent at birth - discounting parents' or benefactors' assets, ownership of which can be transferred within the framework of an arbitrary legal system). Only information (which can be doled out or withheld for coercive purposes) and labor involve the equality with which humans have inherently. Unless, of course, we lived in a world where wealth was always obtained via information and labor - both gained and employed honestly - and not through offensive force and coercion.

Acquiring information and applying it through labor requires adaptation. Actions themselves are a form of adaptability insofar as they are responses ('correct' or not) to external stimuli to the individual.

Since, in regards to interpersonal affairs, all individual humans are inherently equal it follows that the use of the term 'better' is arbitrary and contextual. No one is intrinsically 'better' than anyone else without some contextual, delimiting qualifier. Someone may be better than another at performing a particular task or grouping of tasks, but each and every one of these is ultimately a man-made construct.

One may be a better runner than another but the qualification is arbitrary in that we must look at the arbitrary rules we outline for the performance of a competition between individuals to see who performs better in said competition. One may be faster (at the time of a competition), but one may also run longer, one may have better 'form' (as we arbitrarily define it), etc. One may have longer legs, whereas a shorter-legged person may actually move their feet faster.

Using the term 'better' implies a valuation which is in itself an arbitrary process based on personal self-interest, i.e. what is more and what is less preferential to a given individual.

This is how we develop purpose - by giving value due to our preferences to our desired outcomes given particular circumstances which we perceive from external stimuli and apply the integrated concepts in our ideospheres to reach decisions via cost/benefit analysis on how to act as responses to said stimuli to adapt to said existing circumstances. This continual feedback loop involves more and more complexity as our understanding of our external stimuli/circumstances (and all the aspects that comprise them), our perceptive and sensory faculties, our ideospheres and desired outcomes, and the why for of each increases: i.e., information is power. QED.