I disagree. The article is merely spinning the results based on their own bias.
“We’ve definitely worried about that,” Shafir says. Science, though, is coalescing around the opposite explanation. “All the data shows it isn't about poor people, it’s about people who happen to be in poverty. All the data suggests it is not the person, it's the context they’re inhabiting.”
Shafir is making a non-statement here. "poor people" == "people who happen to be in poverty". This statement does not disprove that people's monetary reasoning is a factor.
Also, science does not coalesce, nor does data suggest; these ideas are derived by the people running the study.
I do not see where in the study people who were good with money were subjected to the demands of poverty had their IQ decrease: that would be more telling. Merely saying that people who are recently working with or comfortable with large amounts do better with on-the-spot questions about large amounts, than people who are not as familiar with those sums is not proof of an IQ drop due to "poverty load".