The emergence and sharpening of Tamil nationalism from the 1940s to the 1980s is a complex tale which cannot be easily summarized in a few strokes. It is a tale of Sinhala extremism at one pole and Tamil extremism at the other pole feeding off each other. At the same time, the divisions within each extreme (that is, the existence of several competing parties with chauvinist positions) disabled steps towards moderation. Moreover, this major strand of political contestation – the Sinhala/Tamil divide — was complicated by strands of Leftist and Naxalite thinking that encouraged both Sinhalese and Tamil youth to move towards revolutionary struggle.
via: http://groundviews.org/2015/07/23/targeting-lanka-playing-ball-with-tamil-extremism-2008-14/