No satistically your argument makes sense. The sample size is too small to draw any broader based comparisons. However, as you said it's now politics and the end result is all that will be focussed on. Most people, and politicians also don't factor in the cultural differences between the services, they think they're all the same just different uniforms. The Marine Corps is less accepting of failure, but they can afford to be because they're so much smaller. They also have a disproportionately smaller budget so they don't have the money to run people through courses multiple times. The US Army has to have the numbers because of their sheer size, this requires them to find ways to remediate failure and their budget allows them to give soldiers multiple "bites at the apple".