It's just one glaring example of lazy writing and storytelling. I just don't understand how they story-board that scene and not have someone in the room speak up and say, "hey guys, this is a really dumb concept, why not just use larger photon torpedoes or some sort of missile to deliver the payload instead of bombers that look like they were straight out of a WWII movie?"
Similar to the whole space chase bit, it's just lazy. They even have one of the First Order officers explain that the Resistance cruiser is lighter... in space... with no gravity. Why not just have the resistance get caught in a pincer move and evacuate as many as they can to the abandoned base? They were already caught in a trap because the First Order could track them through hyperspace... the whole running out of fuel thing was lazy writing.
I get that, going back to the original Star Wars, you have to let some things go for the sake of cinema. There's gravity on board all space ships, X-Wings and other craft can somehow maneuver just the same in gravity on a planet than they can in zero-g space, there are sounds and fire despite being in a vacuum. It would be cool if everyone on board the Millenium Falcon was floating in zero gravity, but it would have been virtually impossible to film back then. This film just crossed that line more often and more egregiously than previous Star Wars films.