But when asked for opinion everyone will be wanting to be treated fairly- except those who want to take advantage of others i.e. the oppressors.
Excellent point. Although you are forgetting about the oppressed people who are convinced that they deserve to be oppressed. Some, like in the Hindu caste system, believe the gods have set the order of society for very good reasons and therefore there is no need for them to revolt (and if they are really good and do their jobs with humility, they may be rewarded in the next life).
Any human society - however small, can not be cohesive without some rules.
I agree. Although the main problem I see is with the lack of logical-coherence between laws within the same framework. What we need to expose are the legal AXIOMS. People are too eager to codify laws that merely have intuitive resonance.