Now's the time to consult the rule book yourself, dear.
Coops put the kick through and Naiqama was, as you correctly point out, in front of the kicker.
However, before Wes made a play at Drugdougall, Coops ran in front of him. This therefore negates the original offside play, because as soon as the kicker of the ball runs in front the rest of his team's chasers, everyone is put onside again.
From the ensuing play, Coops pulled off a one-on-one rake against Drugdougall (or perhaps it was a solid tackle, I couldn't tell from where I was sitting) and then Wes picked it up and put it over the line.
If you want more proof of this rule in action, watch more Roosters games. You will see that almost always, Roosters chasers are offside on kicks. However, Brett Finch (who usually kicks it) screams down the field and thus immediately places everyone onside again, and they are allowed to encroach the ten metre zone, irrespective of whether or not they were originally offside.
I hope that clears it up for you