On one hand, if we suppose this is just a random fluke, and next year 80% of the nominees could be men, then it doesn't mean anything in particular.
On the other hand, if it does mean something, what does it mean?
Are 80% of current science fiction writers female? Having men virtually abandon the field, or be unable to get published, doesn't seem to me to be cause for celebration.
Are men and women present in comparable numbers, but are women writing much better than men? If men aren't learning to write good fiction, that's a problem with their professional education and development, and one that needs to be resolved.
Are men and women writing in equal numbers and equally well, and are women getting a disproportionate share of recognition? That's an injustice, and since the Hugos are nominated by the fan community, of widespread injustice among SF fans. And if that should be the case, it would be understandable that men might be abandoning the field, if they are.
I have no idea which of these is true, but none of them strikes me as occasion for rejoicing.