You have a point, but it's explicitly not what the author did. His screenshots show him replying to each of the tweets, asking to talk to their authors, and he

You have a point, but it's explicitly not what the author did. His screenshots show him replying to each of the tweets, asking to talk to their authors, and he goes on to tell their stories in the article. If anything, this shows how valuable a research tool Twitter can be when used properly.