The link you posted is not a peer-reviewed paper, just an opinion piece. Also, since it was posted 2 years before the paper in question, I have doubts about how relevant it is. It was posted 2 years earlier. However I do note that it still quotes from Keigwin (see my comments re his work on the Sargasso Sea above).
The quote I gave was directly from their methodology. Let me repeat it again.
"Table 1 and Figs. 1 to 3 summarize the answers to the
questions posed here about local climatic anomalies.
For Questions (1) and (2), we answered ‘Yes’ if the
proxy record showed a period longer than 50 yr of
cooling, wetness or dryness during the Little Ice Age,
and similarly for a period of 50 yr or longer for warming,
wetness or dryness during the Medieval Warm
Period."
That is a direct quote from their paper. So are you saying that it is sound methodology to count a period of both wet and dry as an indication of both warming and cooling?
Specifically, do you doubt the statements of Argentinian glaciers, Chinese cultivation, and stalagmite composition in South Africa? What is your reasoning in each of those cases?