I just don't understand why people are STILL so baffled as to why competition finish is cheaper than satin or double cut. Its a lack of surface finishing, so you have decarb.
This is a pretty clear example of a failure to to treat your blade properly. Something like Tuff Glide will work better than straight oil, as its more resistant to coming off.
As far as fixing it...... some people have mentioned scotch brite, some have mentioned naval jelly. My suggestion? Use a chelation agent like Evapo Rust. It'll eat the corrosion without eating everything else. Dunk the blade in it for a while, it'll eat the rust, pull it out, rinse it off, TREAT IT, and you're back in business.