Superstition
A lot of cultures back in those day had strict superstitions. For the people of Easter Island, this one was extremely important to them. If for any reason the Moai were to fall, it would not be put back up. Parts of the island seemed to represent this. On the other hand, other parts of the island seem to show that the Moai were put on. It’s also said that the Japanese donated a lot of money to rebuild a platform so that the Moai could be upright for photo and tourist purposes.