Why do insurgents mostly win?

You that there a few insurgencies going around in the world, like the one on Iraq, Syria, Philippines, Thailand, some in Africa and also in Pakistan's Baluchistan and North West Province (now called Khyber Pakhtonkhwa or KP for short) and in Afghanistan to name a few. Every insurgency is different and so are the individuals involved in it. Some have genuine complaints against the state they are fighting against and some are just plain criminals who need to be put down first with dialogue and then with force. Some insurgents may be called freedoms fighters by some and insurgents by some. But once the insurgency starts and you have no option but to fight to the end for the integrity of your country and to stop the unwanted bloodshed. Insurgents cannot succeed on it and it depends upon the financing and backing of influential and rich individuals inside and outside the country and sometimes some so called enemy countries. Most of the insurgents are fighting for some cause and in that because they have this tendency to make collateral damage which can cause embarrassment to the government but not to them as they don’t care about civilians dying because they consider it a minor headache in order to achieve their goals whatever that maybe. But on the other side, the government forces have their hand tied because they have not only to fight the insurgents but also to protect the local population and not to commit human rights violations at the same time.