I would disagree here. A stronger opponent that values player skill in winning should be challenging themselves to be better players constantly which they are not doing by playing against a weaker opponent with a stronger army. As the weaker opponent will not be capitalising on their mistakes making the stronger opponent become lazy when playing an opponent of equal or greater skill. Taking a 'handicapped' army will ensure that they are not relying on any crutches that they may be dependent opening their understanding of the game so more list building building options will be open to them and they will be more likely to be able to find the list that drives the meta going forward.
Therefore, crushing weaker opponents helps nobody but someone who needs their ego stroked as the weaker player is more likely to quit the game in frustration instead of growing their skill over time and 'getting good' and the stronger player wastes their time and effort because they were not able to match wits with their opponent on an easy win that was not in doubt before the game began.