Well, thats not entirely true. "Community" infers co-operation amongst the people within that community.
Iwi did have their own community - but Hapu tended to have their own defined territory. Given they were essentially a stone age, roaming, tribal, warring people their territory tended to overlap other Hapu territory. This of course resulted in disputes. As a community some disputes were settled by mediation. As an enlarged community the disputes were settled by inter-marriage. And as separate communities they were settled by warfare. Thats how they ensured they didnt succumb to starvation or poverty
New Zealand, with this Iwi / Hapu structure was a hostile environment pre-colonisation. Complete with leaders, commoners and slaves. And within that structure the use of language was limited depending on where in the hierarchy you sat. The most obvious / media driven published being speaking rights - or the lack of rights of women on speaking during a powhiri.
Arguably the more things change, the more things stay the same.