In the ravagers ships there were only males, sure, but they are pirates.
And? Is there a reason pirates have to be limited to men only? It's fiction.
I wouldn't say a 'reason'. There's no need, no obligation. It's just something we can say 'ok, ok, then they imagined pirates - in space! - and imagined only males, that makes sense somehow'.
And how does it make sense? Because people are used to seeing all-male groups, in whatever context. If it had been an all-female pirate crew, I bet you there would've been A Reason for it. As someone who is not a man, I could tell you how tiring that it, but it's hard to fully understand the feeling if you're not part of an under-represented group yourself. It's bad enough there's still sexism and gender discrimination in our reality, but on top of that we also have to accept it in works of fiction in other realities. Men are treated as the 'default' gender. A group consisting exclusively of men—be they pirates or anything else—is completely normal and 'makes sense somehow'. No explanation needed or given about the absence of women. A group consisting exclusively of women needs A Reason for existing, An Explanation about the absence of men. Perhaps it's an all-female species, or for some reason the women hate all men, or the men all went off to war and the women were left to fend for themselves, or some other Reason.
How many mainstream films that weren't marketed mostly to women can you name that have more female than male characters? Both among the main characters and extras? There's been research about the proportion of female versus male speaking roles, and how much they each speak. It's not very equally divided. At all.
Last but not least: there's no more an obligation to include women than there is an obligation to include men, but you don't need a reason or an obligation not to have an all-male, all-white, all-straight, all-cis, all-whatever cast. Even if the diversity isn't explicitly touched upon in the plot, I like to think a diverse cast enriches your story.
I'd apologise for ranting about a film you enjoyed a lot (and you have every right to enjoy it), but it's so. tiring. that the absence of women is taken so much for granted that it doesn't even need to be justified with the slightest handwave, while the absence of men is both rare, noteworthy (both in-universe and among the real-life public), and almost always justified with A Reason.