You're implying that your baseline scenario is a constant absolute number of poor people in the world.
But that scenario is not really constant. If things are getting neither better nor worse, the children of the poor are as poor as their parents, and the absolute number of poor people keeps climbing.
If nothing got better, the number of additional poor people would have been at least 611 million, and that is an under-estimate because poorer people have higher fertility rates.
So yes, "only" 371 million more people in poverty necessarily means things are getting better, when sheer demographics without economic growth would have pushed the number 2x higher.
However, according to your own analysis of the poster's source, the absolute number of people in poverty has increased a lot.
>In short, the claim that poverty is getting worse is utter bullshit.
371 million more people in poverty is not "getting worse"?