Depends on societies and degrees. In the US, "Dr." was (I haven't lived there in decades) used only to refer to medical doctors. My engineering professors were sometimes doctors and sometimes masters. We just referred to them all as "professors."

I think your critique would be valid if Mr. Maynard referred to other scientists by title (in this or other articles) and only left out Dr. Ebrahimi's title. I confess I did not research his other works, if any.