> When the benchmark changes, you should ask 'why.'

The article goes into detail about why the poverty line changed. You must have skimmed past the secrion titled "How the World Bank sets the International Poverty Line".

The TLDR; is that it is at root based on the median poverty line set by the government of very poor countries (which is calculated in a complex way that is explained in footnotes and cited articles.)

At root, it isn't NGOs that caused the number to change, but it was inderectly caused by changes in how poor countries measure poverty themselves.