From what I've heard about a lot of global freight contracting, it seems like there's a lot of favoritism - with ocean freight, for example, when ships are packed, you're not getting your shipments onto them unless you have good relationships with the carriers/brokers/other folks in the chain who can make it happen for you. I suppose blatantly taking kickbacks crosses the line, but it definitely seems like an industr…
I would be surprised if there was an "industry" without kickbacks.
The common theme is that there is usually a bottleneck, monopoly, gatekeeper, or government-mandated middleman. This is what enables the kickback scheme to work without the threat of clean alternatives competing with it.
Ports are ripe for corruption and kickbacks because there aren't many of them. If you want to get your cargo in or out, you have to go through a nearby port. Trucking the freight to a different port is more expensive than any bribes/kickbacks/corruption (by design) so people just settle and pay it.