In college ball you got a guy for 4 or 5 years tops, you can't afford to have a speed WR add significant weight in exchange for strength because if it causes a drop in speed you effectively lost a year of the guy's elidgability tweaking with him physically. Better to tweak with them technique-wise where the risks aren't so great.
Getting stronger doesn't cut your speed. If anything it will add to it. Putting on excess weight that's to much for your frame will do that but simply increasing your strength won't, as evidenced by the fact that Lelie is bigger and stronger now but just as fast. I'm responding to what the article says; that Lelie started hitting the weights this offseason when he saw the film of him getting punked.
That seems to be a question without an answer.