Was Hamas not democratically elected by the Palestinians, taking over Gaza after the Israeli pullout? Had any Tamils who opposed the LTTE left the northeast or the country as a whole? You bet.
The lines between these organizations and governments is obscured at best. What the Palestinians in Gaza have and the Tigers had are pseudo-states, lacking only formal recognition, and, in the Gazans' case, control of borders and civil airspace. In any event, the point I was trying to make was that the Israeli-Palestinian/Arab conflict has been turned into a much more contentious issue than any other conflict in recent history, with a lot of support going to the Palestinian cause, whereas the similar Sri Lankan civil war did not see the same outpouring of support for the Tamils in the region. The similarities are astounding; you'd think the UN would issue more directives against Sri Lanka by now.
While there are similarities, there are also important differences. Firstly, and probably most importantly, the international community has, as far as I know, never recognized Israeli sovereignty over the West Bank and Gaza - the Sri Lankan government's claim to the entire island dates back to independence and is (again, as far as I know) universally acknowledged (not to say there isn't any support for the self-determination of Sri Lankan Tamils). When it comes to international law, the Israeli occupation of Palestinian territories is illegal, whereas the Sri Lankan government's occupation of Tamil-dominated areas of the island is completely legal (though the ways in which the government enforces this occupation might not always be). The international community must treat civil wars differently from illegal occupations lest they violate a state's territorial integrity (although given what happened in Kosovo, it wouldn't be unprecedented for the international community to get involved). Secondly, the Israeli-Palestinian conflict takes place on land the three largest religions in the West (Christianity, Islam, and Judaism) consider holy - Hindus and Buddhists killing each other in some island nation off the coast of India just doesn't have the same immediacy to Western culture. Westerners may have emotional attachments to the "Holy Land" based on religious beliefs - Jerusalem, Jericho, Bethlehem, etc., we know the names of these cities already and they carry thousands of years of baggage. How many people in Canada, the US, Europe, etc. have ever heard of Jaffna?
Finally, the international community has been involved in the Israeli-Palestinian conflict since before Israel even existed. It has always been there trying to divide lands between the two parties, though the dividing lines have shifted many many times. Israel's expansion into Palestinian territories (and even further into Sinai and the Golan Heights) has always occurred during conflicts with neighbouring nations. Though Israel rarely started these conflicts, it is not legal under international law to annex territories occupied during wartime. The Israeli-Palestinian conflict has been an international conflict since day one. The Sri Lankan civil war has been, comparatively, much more isolated. While Britain's role in laying the groundwork for this conflict during the colonial era might be an interesting area for further research, and while the conflict certainly has spilt over into neighbouring countries (especially India), it is still widely viewed as being a domestic matter. The international community can only do so much to intervene in the Sri Lankan conflict while the government controls who gets into and out of the country and where they can go, and there is no internationally recognized government for Sri Lankan Tamils to lobby on their behalf (no counterpart to the Palestinian Authority).
Intervening in the Sri Lankan conflict would be difficult to justify as governments would have to completely blind themselves to international law (though, again, NATO and the UN's involvment in Kosovo undermines this argument). It's not that I think we should take a laissez-faire approach to the situation there, but there are reasons why the Israeli-Palestinian conflict has such great sway over our politics here in a way that the Sri Lankan Civil War (or, for that matter, the Nagorno-Karabakh conflict, the conflict in Western Sahara, etc.) simply cannot at this point in time. In general, it's just a lack of knowledge on the parts of your everyday citizens in countries like ours (how many people here were actually aware of the Sri Lankan conflict before the Tamil protests last year?).
And, of course, the Israeli-Palestinian conflict and the debate surrounding it is charged with words like "anti-semitism," "islamophobia," and "apartheid" - words we all understand.