Why were the matoran so childish on Mata-Nui? Shouldn’t one thousand years of fear and work harden them to be more mature? Even the Toa, memory-less, empty beings are seen to have more wisdom than the actual inhabitants. Do the Turaga just keep them that way?
Why are matoran on Metru-Nui, Voya-Nui, Mahri-Nui, and Karda-Nui so much more mature? Is it because they weren’t down-graded by Makuta in a major setback?
Mine’s just a guess, but it’s probably just because 01-03 had a more light hearted atmosphere, and the fact that they’re so short made them kinda look like “kids”.
In addition, the Matoran were surrogates for the intended audience, which was 8 year old kids. The Toa were who they aspired to be, but the Matoran were closer to who they are.