bitcoin and other cryptocurrencies are being used in the modern-day slave trade.
He could host an address about how a large number of major clothing companies are complicit in the slave trade, but instead he chooses to discuss a form of money which is not at all responsible for the slave trade and cannot be practically stopped from existing.
Seems pretty pointless to me.
effort led by Pope Francis to eradicate slavery entirely by 2020
That's impossible. All that you can eradicate is
known slavery (as in known to authorities). When there's seven billion people, there are going to be problems. Unless of course you had so many cameras in the world that everywhere was being monitored at all times (including in private property).