Their objective is not to target and assist the people who need the most help in getting into hacker school, like the most socioeconomically challenged people in your example. That would pose a number of problems and concerns.

First of all, it would require more outreach. It would also be slower and more difficult, for factors like lack of transportation, communication, or english as a second language, just to name a few. Finally, it would be politically unwise to snub certain groups (feminists, black coalitions, etc) that are much louder and more organized than other groups or individuals, regardless of whether they are in more need.

Basically: it's both easier and more attractive to support the most vocal minorities, and it's much harder to support the people that are actually in the most need.

And yeah, people tend to vote their feelings here. You will get a million more upvotes by supporting someone's misguided cause than you will by calling out the illogical motivation.