Of course, if threats or violence were used, there had to be a purpose: getting information or food, trying to deter the population from future hostile acts (I don't insist this really works).

In a time when beating soldiers for punishment was just normal in most armies, as well as was beating subjects in civilian life, people of the lower classes, including peasants, had another view on corporal mistreatment than we do have today. Of course, still they didn't like it.

From Scharnhorst, Militärisches Taschenbuch zum Gebrauch im Felde, 1794, on detachments on a secret march (p. 40):

Local guides will be taken in the night out of their hourses [...] and they are not set free until they cannot denounce us any longer, and even then they will be threatened that if they betrayed us, they would be massacred and their houses burned down. But they shall be treated as kindly as possible [...] Concerning the peasant who discovers us [...] he will be set free under the menace that, if he betrayed us, we would avenge ourselves on him and his family.

However, I have got the impression (impossible to prove it) that the Napoleonic period was a kind of turning point towards a better treatment of enemies and civilians, maybe caused by the introduction of general conscription and the influx of members of the wealthier classes into the armies. Of course this was not an abrupt change, but brutal and "kind" treatment was found side by side. And, at any time, in every 1000 men with weapons which you send somewhere, there will be at least one man who misuses his weapon.