Thanks for sharing the article. It's such an interesting read.

I simply think that being harmed is when someone endanger you; whether it is your life, your reputation, your physical, etc including your emotion. The damage is higher and may lasted for the entire life. Verbal abuse is one of the example.
being offended is when someone hurt your feelings, but not causing any danger. I consider this as an insult that you can forget easily. In some cases, it also can be denial, for example like a positive criticism you cannot accept.

I admit the article is kind of vague, but unaluna has explained this clearly (to me). Just putting my two cents here.