Stop Hate Crimes Act of 2021 This bill lowers the statutory burden of proof for showing intent with respect to a federal hate crime offense. Current law makes it unlawful to willfully cause bodily injury, or attempt to do so using a dangerous weapon, because of the actual or perceived protected characteristic (e.g., race) of a person. In 2014, the U.S. Court of Appeals for the Sixth Circuit held that the because of standard requires proof that a person's actual or perceived protected characteristic was the sole motivating factor in the offense. This bill replaces the because of standard with a new standard. Specifically, willfully causing bodily injury, or attempting to do so using a dangerous weapon, is a hate crime offense if a person's actual or perceived protected characteristic was a contributory motivating factor in the offense.