An excellent summary of the emergence of extremist Buddhist groups is by Kalana Senaratne in an article titled ‘The ‘Mad Monk’ phenomenon: BBS as the underside of Sinhala-Buddhism’.
In a complex artcle describing aspects of the Bodu Bala Sena (BBS), the Buddhist Power Force, Kalana Senaratne makes some important points. The following descrption of the problematic nature of Buddhist political engagement is to me a point well made:
‘But the more fundamental reason for the emergence of Sinhala-Buddhism, as well as groups such as BBS, has to do with the inadequacy of the true Buddha-teaching for contemporary political engagement, especially in an identity-seeking, identity-promoting multi-ethnic and pluri-national political setting. In other words, the teachings of the Buddha woefully lack those elements with which you can zealously promote, protect, construct your own identities, your own political interests and prejudices, or engage in contesting those promoted by other ethnic and religious groups (more so, in the contemporary state-centric geopolitical framework). The Buddha-teaching is unhelpful in this political struggle: since that teaching is one which, inter alia, promotes as an ultimate goal the ceasing of greed, hatred and delusion, the realization of all identities as constructed identities; in other words, it is a teaching which helps you to expose the artificial and constructed character of all identities, for they are all without self, without an abiding and unchanging self or core. So from the Buddha, you don’t get a clear teaching on how to defend your state and its sovereignty, how to increase your own kind, how to protect Buddhism, how many times to pray during a day, etc. Even the very idea of ‘protecting Buddhism’ the way it is sought to be done today would be meaningless for the Buddha.’
The article also appears here.