A joke about putting MacArthur under Wellington ends with the suggestion that he might become Wellington's cavalry commander. The accompanying quip alleges that Wellington put officers he disliked in charge of cavalry because they would get themselves killed. That is offered as a humorous explanation for poor British cavalry performance in the Napoleonic Wars. The criticism concerns the effect of personal dislikes on officer selection, rather than establishing a deliberate policy of sacrificing commanders.
Notable Point · 1:07:41-1:08:12
Wellington's cavalry appointments and command quality
A humorous MacArthur counterfactual becomes a caution about how officer selection can weaken an arm of service.