If '"Creep" is just the next step in the bullying ladder' then there should be far more examples of women calling Stallman 'fat and ugly' than there are of calling him a creep.
What limited examples I found of calling Stallman 'fat' appear to come from males who also use, eg, racial or ethnic slurs against him.
The observed evidence therefore is not that there is a single ladder, but that there are multiple ladders, and "creep" is a different ladder than "fat" is a different ladder than "ugly".
Let's also not pretend that Stallman didn't have a decades long history of behavior which most other people of similar weight and beauty don't have.