Seriously? Our infrastructure is crumbling, billions of people still don't have enough food or clean water. Diseases, even curable ones, are killing people every day and you have to ask "To Do What?"??
Give me a break. Stop gazing at your navel for 10 seconds and go out and interact with the world. I guarantee you'll find a problem that needs fixing.
Of course, most people learning how to code will not tackle these problems in the first place. The incentives are such that it's more rational to create yet another zero-sum ad-based social-app-for-dogs project. Even the smartest programmers of our generation are probably working on some way to strengthen target advertisements or some other "late-stage capitalism" product that is not useful in the bigger picture, or even constitutes a downright drain on resources. But who can blame them? Without money you are treated like a subhuman creature, with enough of it you are almost a God.
And what % of tech startups are tackling these problems?