I'm pretty sure that's WAI. Commercial, as I understand it, isn't the same as "Civilian". The civilians use it, but so too does the military.
Keep in mind, to have a Drop Ship be commercial, it must have at least 3 months deployment, use only Commercial Engines (big, slow, can't use Military Jump Drives), only commercial damage control (twice as big, but rated the same), only commercial hangars (bigger, needs maintenance modules for fighters / military ships, doesn't reduce deployment clocks for military ships), can't have any weapons other than CIWS, and can't mount any sensors bigger than 1 HS (50 Tons).
So, yeah... that's a lot of restrictions. Even if it's a bug, I'd be in favor of keeping it that way anyway. Such dropships would be in effect a highly-specialized design.