The blog post basically says static stretching during a warm up makes you weaker pre-sporting activity.
Well, of course it does! The idea of stretching is to lengthen muscles. Muscles work optimally in their mid range, so the longer the muscle, the less optimally the muscle is going to work!
This is easily demonstrated when looking at the structure of sarcomeres, the muscle fibres.
This means the muscle is not going to contract as strongly as it would, therefore be weaker.
The idea of stretching is to make muscles longer post activity. These muscles are not going to stretch very well cold, therefore they need to be warmed up first. This is why it is best to stretch as part of your cool down routine, to prevent DOMS (delayed onset of muscle soreness) and speed up recovery.
Rant over! :P