That "charity ship” claim is a fabrication by right-wing media that has no basis in truth and has been even thrown out of court in Italy. Please stop perpetuating such lies.
What is actually happening is that they are paying Libyanese mafia militia for illegal push back operations and they don't want witnesses for that.
https://en.wikipedia.org/wiki/Purchasing_power_parity
It means that the same goods and services can cost a lot less in some countries due to various factors.