Without this rule, the amount of starships being submitted is close to 100% of all starships being submitted. Essentially civilian ships have almost never been made except for as a result of the rule.
Nashoba's made a lot of freighters and other ships by Geshrinari to pair with the military ships he added to the SAoY, it's not fair to him if we give all the other ship builders a pass.
It doesn't have to be made by NAM, and it doesn't have to be an advanced submission like this with sub-articles and such. A nice civilian shuttle would do. I'd also accept Kuvexian ship pages since we're desperate for those.