Protecting Our Communities from Gang Violence Act of 2021 This bill makes alien gang members inadmissible to the United States and deportable. It also authorizes revoking the citizenship of certain naturalized individuals who are members of a criminal gang. The Department of Homeland Security may designate a group or association of five or more persons as a criminal gang if one of the group's primary purposes is the commission of certain crimes, and if the group's members have committed such crimes in a continuing series of such offenses within the past five years. The Department of Justice shall take into custody any individual who is inadmissible or deportable due to an association with a criminal gang. Individuals associated with a criminal gang shall be ineligible for asylum or temporary protected status. Prohibitions on removing an alien to a country where the alien's life or freedom would be threatened due to factors, such as the alien's membership in a particular social group, shall not apply to individuals associated with an alien criminal gang. An alien affiliated with a criminal gang shall not be regarded as a person of good moral character for immigration purposes. If a naturalized person becomes an associate of a criminal gang or has been convicted for or admits to certain criminal conduct within 10 years of naturalization, such conduct shall be prima facie evidence sufficient to revoke the order admitting the person to citizenship in the absence of countervailing evidence.