People with xenophobia experience significant, sudden anxiety and distress when they are around strangers. They often go out of their way to avoid seeing, interacting with, or even thinking about strangers. This type of avoidance can negatively affect major aspects of day-to-day life. For example, someone with xenophobia may find it hard to function normally at work or in social situations.[3]
I would say this is a case of Xenophobia, an irrational fear of strangers.
Xenophobia