I believe passive, until the need for an army. I think Hive predated humanity, and has every intention of existing far beyond human's existence. I think the vex/darkness/and even some of corrupt Vanguard are the real problem. Even knowing the Halo plot twists (how the Librarian and Forerunners became both good guys, and ultimate evil, or that little ghost-like dude in the archives became one the bad guys for a while), it is possible that anything in Bungie's universe can change on a dime.