If you look closely, you can see pillars in very much like the one in those empty stations. I think that they took over the stations and added a centrifuge and other things (out of pure flashy, of course) and that, pirates are, in fact, a fungus. Seriously, think about it. You never see one of them, because they grow inside the ship! They don't have a logo, because they don't need one, they're a fungus!
The tentacles? I think those are large pirates. These ones, when broken open, release spores. The automated turrets, by the way, are defending the loot. The ones on planets are a non-sapient subspecies.