The chant started several years ago in garbage time, the only time Scal ever played. Like has been stated, there has always been an end of the bench fan favorite who fans wanted to see get shots/points late in blowouts, the precursor to Gino.
The problem is, and it shows a high degree of ignorance on the part of many fans, is that in recent years, while Scal has played sparingly, his minutes have been important ones, at important parts of the game. Unfortunately, this has been lost on the chanters, who treat every time Scal touches the ball with a palpable roar for him to shoot, even if he is guarded or 30 ft. from the hoop. That people would even want him to chuck it up in an important part of the game is hard to fathom.
I don't see it exactly as mocking, most of it is genuinely affectionate, just very misplaced and ill-timed.