Pirates are not a single, organized group, but rather a number of smaller bands that cooperate, compete or fight with each other as their interests dictate.
As is often the case among the M’rowans, the distinction between legitimate military forces and outright pirates is often extremely fluid: A warship may be sent to destroy a pirate band one week, only to turn around and start acting as pirates themselves the next week. Most M’rowans see no particular problem with this.
Even so, a considerable number of full-time pirate ships with no particular clan attachements exist in the Commonwealth, making any form of space travel a fairly risky proposition. Most merchant freighters are armed, with guns that of course can be turned on other merchant ships if trade is slow…