Recently, the Sri Lankan government's military captured a satellite base from the Tamil Tiger rebels, prompting analysts all over the world to ask, "why the heck did the Tamil Tigers have a satellite base?"
The US, EU, and India all put the Tigers in their lists of official terror groups, but nobody seems to care too much about the group, as they're mostly nobody's problem but Sri Lanka's (who nobody cares too much about).
Ultimately, the Tigers are a separatist movement that uses terror tactics, which makes them fundamnetally different from Islamic Extremists in a few ways (that have been sadly conflated by the wanton use of the word "terror" in the past 7 years). The first is that they have a limited and well-defined political agenda (the separation of a certain geographical area from a government), which makes them plausibly reasonable to deal with at negotiating tables. The second, is that they're a problem for a very limited number of people (in this case, Sri Lankans), so it's very easy for other countries to ignore them. This is in contrast to, say, Al-Qaeda, which seeks revenge on innocent non-Muslims for the deaths of any Mulsim at the hand of non-Muslims in history; or Hamas, which seeks to irradicate the Israeli people. "religious genocide" is not a goal that one can negotiate with.
The Tigers may be on their way out, thanks to the persistence of the Sri Lankan military and token help from a few friendly countries like India. They are definitely bad dudes that do bad things to good people. My primary worry is that cases like the Tigers are going to increase the terrorist-separatist conflation, allowing countries like China to brutally crack down on anyone in Xinjiang or Tibet thinking about waving a flag of their own.