The PKK in Turkey is another example. Kurdish militia that had support of the local population, but was no match for the Turkish military. If the entirety of a country revolts, that's difficult to do anything about, not least because in that case the military is likely to defect anyway, making the question of a military vs. militia fight moot. But in most realistic scenarios a militia uprising is only by part of the population, which is a lot easier to defeat.
Comparing the Tamil Tigers and a popular uprising of 200 million armed Americans is laughable.
Your mistaken notion that a rebellion can't fight a sophisticated military has been decisively disproved over the last decade in the middle east. Plausibly debated 15 years ago but now we know you're wrong.
ISIS took control of a large part of Iraq and Syria and they started with small arms. They took over army bases and stole gear (didn't think of that?). IDF has been throwing the best technology in the world at Hamas for decades. They're stronger than ever because they have popular support.
Suggesting that the U.S. military would fight against a popular uprising is beyond crazy and entirely ignorant. You can't know how our military works, or who it's made up of, and think that. This is crazier than any common conspiracy theory you can think of.
If there is ever a simple uprising in the US, I would completely agree with you, it would be next to impossible to get the armed forces in the USA to fight against a general popular uprising.
If it is more fragmented then it gets more complex as national solidarity breaks down at that point. Sure the army won't shoot Americans, but propaganda can start to redefine who counts as American.
ISIS did take over well equipped army bases with AK-47s, however only because the people with the equipment were not trained and ran away instead of using it.
And the IDF has only ever been in limited engagements against Hamas. They have never tried to completely destroy them militarily.
My point with the LTTE was never that a rebellion cannot fight a sophisticated military, just that if a sophisticated military uses total war tactics, they can utterly annihilate a foe.
What stops armies from doing this against a weaker enemy is not capability, but politics. The US could have nuked Vietnam for instance, but politically it would have been unjustifiable.
Ultimately, it is the attitude and makeup of your military that protects you from them, far more than the personal ownership of guns.
Edit - Regarding common conspiracies. My personal bet at the moment, ignorant and uninformed as I may be, is that there are a bunch of secessionists with power in Missouri and that this explains the bewildering actions of the Ferguson police.
It would seem a very good explanation for the actions of many of the authorities involved in the situation. Though, then again, so would complete incompetence, so in truth I am 50/50 on this.
The peshmergas are an example of armed citizens rising up to defend themselves. Not a counter example. There have been many of much smaller militias in Iraq run by reasonable people protecting their communities.
On home soil it may well do this, but equally it may go completely nuts if it feels subject to a genuine existential threat.
Look to the end of the Tamil Tigers for an example of what a modern military is capable of against insurgents when it pulls out all the stops. - http://www.newyorker.com/magazine/2011/01/17/death-of-the-ti...
And remember that the Tamil Tigers were one of the most experienced of the various guerrilla groups around the world.