"Driving a Prius" is a commonly used joke and stereotype wherein, those who drive this car are said to be "bad drivers" or are said to have something wrong with them, as this car isn't particularly appealing or impressive. Therefore, Perry uses this joke/internet meme to illustrate how men who choose to break the standards of toxic masculinity and abide by the principles outlines on the bumper stickers, wherein they are secure with themselves being softer, cautious, kinder, etc., are often looked down upon and are not regarded as "true men".
