The whole point of invasion is to obtain more resources aka land, material and technology. How would you manage it? Logistics. Who will manage it, including policy and everything in between? The top brass. Who are currently the top dogs here? Muscle brained idiots that don't even know the L in "logistic".
Middle managements in this country are fucked, or more like, this country's fucked.
I have no problem with how the duke sent the MC as a hostage, but the way he berate the MC shows us how stupid and ignorant he was, especially as one of the top of a country.
I don't hate this cliche, happens all the time irl, especially to middle children. But seriously this sucks.