Reddit reviews Irish Society, Anglo-Norman Settlers, Angevin Kingship: Interactions in Ireland in the Late Twelfth Century (Oxford Historical Monographs)

That post is of no value and is not to be taken seriously.

A túath was simply a petty kingdom of the lowest rank, whose ruler, a rí túaithe, would have been subordinate to a more senior king (the word "Rí", king, was used promiscuously in Ireland). I don't even know where this idea of Ireland being politically divided into voluntary associations comes from, either. Irish kings frequently fought over territory and influence, and sought to expand both, formed military alliances, and demanded tribute from their vassals.

Kings were "elected"? Not really. The king's successor was elected by and from within a kinship group -- i.e. a certain subset of the previous king's relatives chose one of their number to be next in line, or Tánaiste.

The post's assertion that "Irish history records peaceful, voluntary cooperation until the barbarous English invaded in the 1640′s AD" is absurdly wrong in so many ways it's hard to know where to begin and it's hard to see how anyone with even a passing acquaintance with Irish history could take it seriously.

The idea that Pre-Norman Irish society was some sort of anarchist idyll is a non-starter. It is correct that there was no centralized state -- the island was a patchwork of kingdoms and subkingdoms, but society was highly stratified, and the "freemen" of landowning/aristocratic or recognized professional status were a small proportion of the population. Most people had effectively no rights or freedoms, let alone to choose their leaders, and were subject to arbitrary demands for food, shelter, military support, etc. from their lords. Even under feudal system peasants had some recourse to the law.

For more serious treatment of these issues, try:

• Marie Therese Flanagan, Irish Society, Anglo-Norman Settlers, Angevin Kingship: Interactions in Ireland in the Late Twelfth Century.
  
  
• Fergus Kelly, A Guide to Early Irish Law.