Do people that migrate to countries but prefer not to speak its common language except when needed realise they are narcissists?

They do not care. They are only in it for the money, and FU to citizens.

I think you need to rethink your assumptions! People who migrate and most will prefer to speak their first language especially with their family and friends from the same country are making an effort to keep their identity alive and often try to pass on to any generations born in their new country an idea of their ancestry as well as education, as it is always good to be able to speak more than one language

THAT YOU just can speak YOUR language is your problem.
Immigrants and anyone else can speak whatever language they want to communicate with the person they want to communicate with.

That they do not want you listening in just means you are nosey.

AS some mention it is not a god idea for immigrant not to try and learn the local language langauge as best they can for many reason.
Communicating with you is probably low on the list.