It's also worth noting that Seuss, Sendak, and Silverstein worked quite a while ago, especially Seuss.
And you always have to wonder who exactly changed kid lit. Since every book does not get accepted, the editor who took a chance on something new should also get some credit. Maybe at the time, editors were more receptive to men doing something new than women?
There are a lot of variables at play here.I really don't take the article too seriously.