He’s responding to how they fight over food. Food is hard to come by in Netherlands especially in hiding. Hunger was pretty common. Since they rely on others to bring food, it’s even worse for the Franks and Van Damms. They are fighting over potatoes in the scene (eat them or not). They are destroying themselves by fighting and putting their needs (eating right then) over the communities (eating later). They should work together and all make the same amount of sacrifices so they can survive. This isn’t their first argument either, and when they are mad at each other they destroy themselves.
Find some quotes about them fighting and that should be good evidence
"provide for the common defence” would be the phrase that was included in the Preamble to the Constitution to ensure a military that could protect our country. Although we take it for granted today, it was not ensured for some time that there would be a military.
