Evil People Island, although disunited internally, was extremely xenophobic. After all, everyone there had enemies; thus, when they saw outsiders enter Evil People Island, if the outsiders weren't like them—hiding from their enemies—there was a high likelihood they would also suffer a mass attack.
Besides, it was no issue for one person to enter Evil People Island, but if it were two people entering, they were bound to be pursued and killed by everyone on the island.
The rules of Evil People Island stated that only one outsider could enter the island at a time; this was also the sole rule throughout Evil People Island.
It was because of this rule that once you sought refuge on Evil People Island, you hardly had to worry about being hunted by your enemies; the only thing to consider was surviving on Evil People Island."