If the person doesn't know Croatian language then, how someone can hire?
Logically, knowing a language does not mean that you live in the country of which it originates.
For example, if I learn French, I am not forced to be in France. I have no doubts that some moderators do live in the country that the language hails from but it is wrong to assume that all moderators, past and present, live in the native country.
You mean anyone can learn a foreign language better than a native person? Also it is a moderator job that require native persons only. I have seen in every forums a native person only being hired.