Red is the symbol of danger, evil, and death. In South Africa, red is the color of mourning. In Amsterdam, it loosely symbolizes prostitution, but is meant as more of a broader symbol of depravity. Red tape is being bogged down by useless details. Red Skull is the nazi-esque leader of Hydra. Red is the symbol of warning in traffic signs and terrorist attacks. When Pharaoh refused to let the Israelites go, Moses dipped his phallus in the rivers of Egypt, and out came the red blood of murdered baby children.
Red Sox are all of those things, but on feet.