The 'revenge' theory of politics has a number of benefits to those who claim it. It removes any need for evidence (you can claim no would admit out loud), it allows to bypass any debate about the core issues (because the revenge claim means its isn't even about the issues), and it allows you to vilify the other side (because only a villainous and evil party would use government policy for such an goal as revenge). Really a perfect mix of unprovable, issue/reason bypassing, and maximizing of emotional response.