Good article, but I think it only partly addresses the OP’s question.
First of all, keep in mind that when the Pope speaks, he is speaking not just to us, but people all over the world. When we in the West think of the poor among us, we tend to think of people who were born in bad circumstances, have had a run of bad luck, or who have been lazy or in trouble with the law.
I believe the Holy Father here was speaking to those who find themselves in material poverty today: those in our own mostly affluent society who have limited income with little hope of improving their lot, but mostly to those in the desperately indigent areas of the world where poverty is more a fact of life.
The Pope reminds these poor that poverty in these conditions is not something to be ashamed of. He also wants them not to slip into despair or use poverty as a pretense for violence or harboring a resentful or jealous heart. If it is truly one’s lot to be poor, one can and should use those circumstances to acknowledge one’s dependence on the Lord and grow in the holiness that is found in not having the burden that often goes with attachment to great possessions.
There is no virtue or vice in being poor, per se. Both poor and rich can be either holy or hellish. The rich have their own problems in gaining sanctity, but the Pope’s words here are addressing the poor.