There are two types of pirates: auctions and game events.
The auction is won by a player and they can direct a raid's target or even collect a bunch of them and launch them all at one or more targets simultaneously. Depends on their strategy.
The game event pirates will seek out the planet with the highest bounty (you can add bounty to specific planets and convince other players to pile onto the bounty to help take down the leading player, etc).
Which one is causing you problems (auctions or game events)?
Which would you like a setting to disable?
We will also be adding a number of other 'threat' auctions and events that aren't pirates (e.g. Sins1 Stellar Phenomena and Minor Factions DLC packs have a bunch of these). Do you want to be able to disable these too or is it just pirates?