Not to say they’ve ever seemed passive.
Most of the time we see the Space Pirates, they’re on some fringe world and trying not to attract attention. This is the first time we’ve seen them so aggressive; it might be all the Phazon they’ve been working with. The opening part of the attack has you trying to escape the flagship that they’re striking, and then you have to rush to defend a military outpost. The Federation certainly isn’t making a show of being the type of force the Space Pirates would fear so.
The reason I replayed Metroid Prime 1 is that what we’re facing down in this game is tied in pretty closely with what the Chozo had to deal with on Tallon IV. Yes, that meteor is roughly the same type! I’m pretty sure it doesn’t have a Metroid Prime inside, but its goal is the same. It’s a good thing this is all happening while Samus is around this time, because we were centuries too late with the last two planets.