Mytilini is normally just a small, sleepy town, but today it’s thronged with people. The town center is a sea of white and blue — the colors of the Greek national flag. More than 9,000 people have followed a summons by the local governor, Konstantinos Moutzouris, and have come from all over Lesbos to Mytilini to protest against the Greek government’s migration policy. It’s the biggest protest in the island’s history. The road around the little harbor is packed with people of all ages. They’re joining forces to make their voices heard and do something about the situation on their...