Today I've been fighting my way through another Tough galaxy (i.e all enemies on Genius, does that have an effect on pirates?), and am faced with the following pirates: 

This starbase, which has about 0% chance of survival against that pirate fleet, has been sitting in their 'chilling' spot, 3 hexes south of their own shipyard (you can see it at the top of the screenshot) for 40 turns or more. Are pirates just not interested in stealing valuable strategic resources? Do pirates not want to raid the unarmed drone mining ships/transports which carry the stuff?

While they don't pose much of a threat (after all, they ignore the starbase and still only move at 2 hex/turn, rendering them incapable of catching any ships passing by), their numbers make them somewhat challenging to take out.

This huge pirate buildup seems to have happened because they don't care about logistics, having 30/10 in fleet. All tiny ships. A little ways away there's another fleet like it, from a different pirate base:

Again, 34/10 logistics.

That's one issue which I actually think probably isn't a bug, but a requirement for pirates to be a viable threat without having actual technological progress. Still, they're prevented from actually being dangerous by still not being able to move, and I'm not sure if that's a bug or a ship design decision - low movement is something the Drengin gimp themselves with also to fit more guns after all.

In any event, reporting this in the hopes of more scary pirates!