It's a stupid misinterpretation.
I guess you read the reply from the team of Scientists that studied the map then...?
I did, and I did a little bit of research behind that "team of Scientists."
1). Captain Lorenzo W.Burroughs was a cartographer for the USAF. He was by no means a "scientist." Him and his team came to an unusual conclusion in 1964 which ended up in Charles Hapgood's book, "Maps of Ancient Sea Kings," a book which is used to argue for an ancient maritime empire, i.e. Atlantis. Hapgood notes the compilation techniques of these maps, how they are taken from different sources, translated free-handedly from different projections, use alternate compasses, and contain errors. Weirdly enough, however, Hapgood was not trying to argue global warming or ice caps in his book. He was trying to find where Atlantis was.
2). The sources of the map are never called into question in any argument I have found. Which is unusual, when a medieval manuscript contains unusual discrepancies, scholarly bodies tend to compare the manuscript with another, its source, &c. The map, according to Piri, was drawn from 8 Ptolomeic Maps, an Arabic map of India, and 4 Portuguese maps, and a map by Christopher Columbus, among others. That leaves 5 maps unaccounted for. Of course, it doesn't matter: Antarctica being represented on the map is a controversial issue; there is no agreement in the scholarly community on whether or not it is Antarctica being on the map. We lack the source maps, their sources or credibilities. We also know of of mistakes that early cartographers have made.
Of course, scholarly methods, analytical deduction, comparative historics--none of these have a place in conspiracy theories. Because these are all logical ways of filtering incorrect conclusions which are based on hunches. Lord knows we don't want silly things like facts to get in the way of truth.
Modern scholars see the southern landmass to be the southern portion of South America, the islands near the Falkland islands. Internal evidence suggests it. The skewing may have been from the awareness of a southern landmass that was never accurately mapped or a bad translation from a polar projection map.
3). No credible scientist has ever made the argument that you're making now. People, who are not scientists, who have analyzed the map 40 years ago have made an assumption and did believe that the map accurately represents Antarctica. This view is not held today. Only amateurs and people with "ideas" about "truth" argue that this map is 100% representational of the world in the 16th century and use fringe evidence which lies outside of the accepted field of scholarly studies and geographical facts.