Yep, Light industry without free port = doing it wrong.
considering LI is the one that supposedly produces most of the basic necessities for the entire population of the sector, besides food and supplies, i'd say there's a problem with it being only worthwhile for drugs, at the very least on a conceptual level.
even with drugs though, it
still has lower profit than HI, despite HI playing a uniquely necessary role in colony building that has nothing to do (in gameplay terms) with its monetary profits. i'm not saying HI should be the benchmark for all industry profits, quite the contrary, but even with assuming that LI is only ever supposed to be built to export drugs, the numbers are still off. not to mention that LI being decent in normal ports and really profitable in freeports would be preferable to it being decent in freeports and completely useless in normal ones, imo.
drugs could also just be moved to something else as well, if LI producing supplies would make it too profitable compared to everything else. Farming would make sense, i think, depending on what exactly these drugs are made from.