The US did this all the time in Syria and Afghanistan. In Syria, ISIS took over oil fields which the organization then shipped to Turkey for sale. The people weren't the target, the trucks were. Because they were being used for a military purpose-the funding of ISIS, that made them valid military targets. And completely legal.
In Afghanistan, the US bombed narcotics production facilities which were used to fund Taliban operations. The people operating the facilities were civilians.
Again, valid military targets, and legal IAW with international humanitarian law.
"No court found them guilty."
I know when I was doing the thing, every target was reviewed by multiple JAG's, intelligence professionals, Ops professionals, and others, before finally being blessed off on by a senior general. And again, it's not the people. It's the boat. The boat is the target.