Borami - I'm with you on this - I read the piece and came to pretty much the same conclusion, it is not a scientific analysis, nor is it an objective study, it is merely one person's opinions wrapped up as "fact".
You could pretty much re-write the piece swapping 1 hander and 2 hander around and it would read much the same and still make sense!
"More versatile- one hander is much more versatile than two hander. With one hander you can hit drive,different topspins,topspin lob,short topspin cross,half-volley,balls on the rise,high balls with topspin or on the rise,and all these different shots are much more easier to execute on one hand (much higher percentage of success), and with more variation .Furthermore , players who use one handed backhand easyly transfer this technique to hit slice and volleys (very difficult shots hit with two hand)"
And you can't dispute that, as those are "facts"