Because it is your civic responsibility to care that such things are happening in your community, and to allocate your political activity, voting, and charitable giving in a way that you believe will mitigate that suffering.
Because if everyone said, "sometimes humans behave badly; why should I care?" we'd be living in a hellscape.
Says who? Where is that written?
I couldn't care less about such problems in my community. I pay my taxes so the city/county can hire people to solve these issues. My politicians have little to no competition so voting for who's in office is largely meaningless in my case.
Why should I spend my time, mental and emotional energy on "the news" when this offers zero immediate benefit to me? Even during watercooler talk if someone says "did you hear about x?" I can reply "no, please tell me about it" without losing any face.
I've been thinking about deleting news apps from my phone lately because I realized I did not actually enjoy or benefit from reading what's going on in Us politics or international affairs. This article cinched the deal. If something is really important then I'll read about it here, on reddit's FP or hear it from my friends/colleagues. Everything else is just noise.
If there is violence in my local community, then its realistic that I could affect some level of change there. For example, I could join a neighbourhood watch, work with local police etc. Help fund a youth club.
On the contrary, if I stay informed on as much snippets of murder, deceit and corruption that happen globally, pretty soon I will feel overwhelmed and rendered powerless.
Knowing about a drug murder in Mexico or a child slavery in north Korea, is not something I can do anything about, apart from feel depressed.