I hate to break it to you, but academic publishing can be political. The political component is smaller in math than in other areas, but not zero.

Here is a study that shows articles previously published by esteemed psychology researchers were rejected when re-submitted under a different author's name, and not simply because reviewers recognized the articles. The papers were subjected to greater criticism when given a different author.

I don't want to exaggerate the effect of prejudice, just to say it cannot be ruled out.