It's a model without a reality to reflect, however.
People don't leave the military by the thousands because some of the neighbors back in their home town switched flavors, and most countries didn't draft or recruit people into units by which church they happened to grow up attending.
Today it is true, but in that time ...
Let say the Austrian, then Austro-Hungrian army was based on the model used in VIC2 :
units were OR Italian, OR German, Or Hungrian OR Tcech (spelling?) OR Slavic.
Officers had to speak those languages , study and exams were implemented for that. A person as the late Field Marshal Von Bohm Ermoli (Marshal of Austrian Empire, Marshall (Hon) of Germany and GErneral of Tchecoslovaquia (Hon)) had to be fluent in ALL of them.
Those units (from the company level up to the Div level) were ethniques based on the language, with specific geolocation recruitement.
Same for France until the middle of the 1980 (I believe it was abandoned officially in 1976/1977; but it took time to implement); because climatic reason : The north east part of France is cold, as low as minus 20 C during the winter with max of minus 47C; the Atlantic coast is extremely Humid, and the southern part may seems hot like hell for soemone coming from said north eastern part). Futhermore, it was also language problems, with many recruit barely spoken the same french as the officiers or the non com officers (in 1985, I had 2 recruits from Compiegne neighboor who did nt speak french at all but Picard , and I had another one From Lille who had to translate back and forth ...)
So yes it may be sound crazed for a youth in 2011, but it sound also real life problem for people older who had to deal with the very same problem not so long ago.
P.S. I named the name of the Towns/Region to make it clear it did happend, and it was real even if it was also 'epyphenomenous' mean rare but not unusual.