I can see the author's point that it is bad to hire job-hoppers at a startup. A startup probably needs people to stay around for their knowledge.
But this is such a terrible generalization. People leave for basically one reason - they will be happier doing something else. Why not make your company the place they will be happiest at rather than blaming those around you?
The author is upset because with "job-hoppers", employers do not have as much power as they once did. This advice is incredibly biased towards keeping the status-quo for the author's own selfish reasons.