At the end of Lizzie Bright and the Buckminster Boy, why does Reverend Buckminster side with the Phippsburg townspeople against the people of Malaga Island?

Mr. Stonecrop describes how much money the island people have taken from the Phippsburg townspeople.
The reverend finds out that Turner’s baseball bat and glove were left on the beach, not the front porch.
Mr. Stonecrop talks about the people in town who would support those on Malaga Island.
The reverend learns that Turner went to the island with Lizzie Griffin, an African American girl.