We don't know that they haven't. If they're in the place of people we know, people we care about? Who knows what they did to the other person, the person who's place they are in. Their bodies could be floating out in space somewhere, and we'd never know. They didn't come and ask for help, they came to take what we have, and leave us to rot.
I'm not leaving them to starve, but I'm not putting them in a position to starve out our people either. This stuff wasn't handed to us Steve. We've worked for most of it.