Alpha Centauri-B III, not Mars, but that's beside the point.
What you said may be the problem, I hadn't thought to look. The only trade good is infrastructure. Colony has a 1. 2/year surplus. I think I'll need to do a civilian contract to move any more.
I had forgot about the industrial "infrastructure" vs the trade good "infrastructure". Looks like that's the issue, though. If I stop shipping infrastructure there with my personal transport fleet, the colony ships will offload enough civilians to need more infrastructure at which point the civvie freighters will probably start running again. Gotcha, thanks for the help!
Yup, that was the problem. Also, setting up civilian contracts got them to start moving my produced infrastructure instead of their trade good.