There are instances where "Fair Play" Should be used. But there are two quite obvious reasons the goal stood.
Firstly, "Fair Play" isn't a rule. It's not enforceable. Yes, being a good sport makes you slightly less of a **** but honestly, how Fair are we supposed to get? Not allowing goals because the keeper wasn't ready?
Secondly, He kicked the ball! Turner doesn't get paid the kind of money he does to jerk around like that. In the middle of Premier League game no less. Kuyt, saw his mistake and capitalised. Isn't that the purpose of Football tactics? Forcing mistakes that you can take advantage of? Is that not what he is supposed to do? I mean, c'mon! This is competitive football for crying out loud. This isn't a case of lack of "Fair Play" this is a lack of professionalism.