It seems to me that the author completely missed Medium's import tool in his/her "mirror your blog" section. The tool is specifically made to prevent SEO issues

It seems to me that the author completely missed Medium's import tool in his/her "mirror your blog" section. The tool is specifically made to prevent SEO issues when syndicating content from your own blog. https://help.medium.com/hc/en-us/articles/214550207-Import-a-post https://help.medium.com/hc/en-us/articles/214550207-Import-a... There's no SEO risk as the author alludes to. This is Medium's tool for dealing with that.