Two - or twenty-two - wrongs do not make a right. Copenhagen was a war crime. The retreat to Corunna was an isolated collapse of military discipline, as were Badajoz, San Sebastian and Ciudad Rodrigo. British commanders in Spain and Portugal were at pains to prevent and to punish looting and the associated crimes whenever they could.
French commanders made sure that they got the lion`s share of what became available.
French - and allied - soldiers looted by habit in Spain because their own army provided them with nothing.
This false economy ensured that the vast majority of the civil populace became utterly hostile to them.
The same thing happened in Russia in 1812.
Not very clever, was it?