But to your point, in any reasonably realistic science fiction setting, I would expect most civilian ships to be armed. It would be a much cheaper solution than state patrols. I’ve seen some calculations that suggest only high value goods would be shipped in space (something you wouldn’t mind paying $100,000 per ton in shipping charges). Small high value cargo is eminently suited for smuggling, and plundering — and this would be consistent with the cargo capacity of the Falcon (even allotting for standard cargo containers pushed barge-like between the forks).

So, a plethora of ships carrying high value cargo is ample reason for arming them. And the primary reason why Age of Sail merchants preferred to go unarmed (weight of gun, powder, shot, and a bunch of crew) wouldn’t necessarily apply to space weapons.