Why is global poverty something the average person should or should not be concerned about?
This is an issue that is not going to go away anytime soon, and it is probably something everyone should be concerned about. Paul Hewson, also known as "Bono", the lead singer of the Irish band U2 has said before that if Americans, or anyone, really, truly believed that "all men are created equal", then we as human beings would be making every effort available to end global poverty. Bono usually speaks specifically about Africa, as he has spent a great deal of time there doing humanitarian work, particularly in relation to getting AIDS anti-virals distributed to those in need--but given the scope of work he has done over the years, it is safe to assume that he would say the same about extreme poverty anywhere.
On another moral note, anyone who knows anything about Jesus of Nazareth knows that he had plenty to say about humankind's responsibility to help anyone who does without or is suffering in some way. There are plenty of examples to illustrate what he believed, among them the following from the Book of Matthew:
Then the king will say to those at his right hand, "Come, you that are blessed by my Father, inherit the kingdom prepared for you from the foundation of the world; for I was hungry and you gave me food, I was thirsty and you gave me something to drink, I was a stranger and you welcomed me, I was naked and you gave me clothing, I was sick and you took care of me, I was in prison and you visited me."
And from the Book of Luke:
. . .when you give a banquet, invite the poor, the crippled, the lame, and the blind. And you will be blessed, because they cannot repay you, for you will be repaid at the resurrection of the righteous."