Why does troy put a stop to Cory's dreams?

Troy stops Cory's dreams primarily out of his own fears and experiences. Having faced racial discrimination and unfulfilled aspirations in his own life as a Baseball player, he projects his insecurities onto Cory, believing that the world will not be fair to him. Troy wants to protect Cory from what he perceives as inevitable disappointment, leading him to discourage his son's ambitions in football. This reflects Troy's desire to shield Cory from the harsh realities he faced, though it ultimately stifles Cory's potential and aspirations.