Two of my ancestors left two different part of Germany in the 1870s (Baden and Wurttemberg, which were at the time separate). They went first to Switzerland (La Chaux de Fonds) in 1874 where they met and funded a family. My grandmother told me they left Germany because of the Franco-German war, however I cannot by any extant imagine why they "fled" : Germany had won the war so there was absolutely no reason to flee, especially not 3 years after peace was established again.
They were probably still in phase with the German government as they had a legal foreign status, and information about their wedding in Switzerland was transmitted to German authorities (or at least it is written that it was).
I cannot really imagine that they left Germany for a reason other than economical, or maybe emotional. Or maybe they disliked Prussia or the new German Empire's government so much they'd rather leave their countries rather than having them overthrow by Prussia ? I really am puzzled about their reasons for leaving.
Their occupations were tailor and cutter respectively, the dad was catholic and the mom protestant.