Sure, we may be busy and the cold calculus of war tells us we benefit more from focusing on where we can expand our hold with less cost and more benefit. But that is what we base our decisions on, then - it's fine if we choose not to help because it's just too costly and doesn't benefit us enough to be worth it. That is the sort of analysis we must do to win.
But it's not fine to make ourselves feel better about it by claiming that there's nothing we can do. We can help them, but we choose not to because it is costly, risky and unlikely to be worthwhile. It's an acceptable decision on its merits, but we need enough self-respect to call it what it is.
Gonna rant for a bit, so please bear with me.
At a the scale we are working at, every choice is gonna be shit. We go one place, people die. We go another place, people die. We stay in one place, PEOPLE DIE. The reason is obvious. The sector has been abandoned by the Imperium for some reason. It could be that the Segmentum itself is endangered. Perhaps some front collapsed and the sector was gonna get cut off. Who knows? But the sector is burning, and it's up to our paltry fleet to save what we can. It's not enough. Not even close. But it's what we can do.
Now, am I happy we are leaving these people? No, I'm not. Just like I'm unhappy about Khornites marauding around a hive world. Or how human worlds are occupied by orks. I'm worried about Naval Bastion Gehault and their willingness to crakc down on worlds as the sector is besieged. I'm leery of fighting the aliens and their 4 ranked shields. But I'm especially angry at how the orks got their hands on a Cobra destroyer we had to dismantle. Very angry about that one, actually. Those damn Orks have more IMPERIAL WEAPONS THEN WE DO. THEN WE EVER COULD!!! Fucking Orks. Feels like they get their hands on more Lemon Russes then the Imperial Guard.
But am I sad? No. I'm
angry. I'm mad that the xenos have Ungaunt besieged. I'm mad that the FUCKING ORKS HAVE IMPERIAL NAVY SHIT!! But I'm not sad, because I know that this is not final. I know that we can right these wrongs. Maybe not now. Maybe we never right them. But we can. And in Warhammer 40k, that's enough.
Okay rant over. Sorry bout the cuss words, but eh. Wasn't feeling good. Hope you understand my perspective a bit, eh? We can't do much, but we are doing what we can. And that is never going to be something I'm sad about.