In football the primary objective is to score more goals than the opposition. That is not the same as outscoring them by the maximum possible margin.
Now if you are one, two, three or so goals ahead you are entitled to go for more because they could score and get back into it.
Or in a league game there would be nothing wrong with going for the biggest possible winning margin because at the end of the season goal difference could be an issue.
But in a cup game, up by seven at half time, show some respect, there is no need to humiliate anyone. Secure the victory, get out of there and into the next round. That is the objective and there is no ill feeling on anyone's part.