To believe the police planted those gloves requires that you believe the police (who were friendly with OJ) after having discovered the dead bodies, planted the gloves both at the scene and at his home and were just “lucky” to have later found a receipt showing his wife had bought him those very gloves.
Since the person who "found" the glove at OJ's house ended up with a perjury conviction, it is reasonable to at least question his credibility.