The honest answer is that it's an apples to oranges comparison, and no one knows for sure how extent from the first half of the 20th century compares to the satellite era. The graph above is one educated guess, but far from the only estimate. This post goes into great detail on the difficulties of comparing sea ice extent measurements back then to now: https://judithcurry.com/2013/04/10/historic-variations-in-arctic-sea-ice-part-ii-1920-1950/ You may not agree with the conclusion, but the reasoning is thorough and well laid out.
What we do know for sure is that the Arctic has gone through cyclical warming and cooling periods that are much more variable than lower latitudes. In the 1980s, the Arctic was in one of its cooler phases, and given the amount of AGW to that point and total variation that the Arctic climate sees naturally, it's not at all unreasonable to assume that some of the warm phases of the Arctic earlier in the 20th century were probably warmer than the final cool phase of the 20th century. Ice extent typically follows temperature, to a certain degree.