This seems to be the popular "go to" comment when you are talking about something that emotionally effects you, but isn't as significant as other issues.
A good example of this comes up when discussing animal cruelty.
See a newspaper article of a dog getting beat up because the owner was a sadistic asshole, and express your disgust verbally? "You shouldn't worry about that, because there are starving children in Africa".
Comment that you are against glue trapping rodents because it's unnecessarily cruel and inhumane? "Who cares about pests when you have children in Syria dying".
Funnily enough, the people who mention such children in worse situations usually bitch about even "lesser" things, how they had a bad day at work, or how their meal at a restaurant was substandard, etc.
There are starving children in Africa - yeah? And? What does that have to do with my opinion about the issue in hand? Do global issues pertaining to famine and corrupt governments mean we should be silent about issues that affect us on an emotional level, which are smaller? Of course not. Children being bombed in a middle eastern country isn't going to change my opinion on issues like people being total f-wits to animals, or people being bitchy in the workplace. It is important having priorities, but that doesn't necessarily mean people should care about only one thing at any given time. I detest both cruelty to children and animals, but for some people who don't give a damn about the latter, this is somehow mutually exclusive??
Some people say that people who complain about animal cruelty are self righteous - well, are they really? I can understand a PETA member who is full on vegan and proclaim meat eaters are evil animal abusers, they are definitely self righteous. But calling out someone being cruel when they are beating their own dog? Prolonging the suffering of an animal in a trap? I mean, isn't there a division somewhere between self righteousness and calling a spade a spade? Where is it?
Those who say things like "but there are starving children in Africa" to someone who expresses concerns about animal cruelty might as well be saying "I don't care about animals, only human beings". At least that is being honest and not trying to force people into thinking they shouldn't worry about stuff like animal cruelty because humans are suffering. Isn't suffering bad regardless if humans are higher on the totem pole?