Less about gun control, more about controlling the guns
Besides the obvious leaning of the two main characters, the point was more or less made by the fact that some guy bought a ridiculous amount of semi-automatic guns with NO ONE checking in on him.
The point being made was that the company didn't care where the guns were going as long as they were getting sold.
Also I think it highlighted how difficult it is to get a favorable verdict for David when Goliath has all the money.