To the person saying that gangs are bunch of morons is dumb, the term "Gangster Tactics" was used many times in German Proganda to show how villainous the people there fighting were (much like Terrorist/Freedom Fighter), the Germans loathed partisans, people who did not fighting in "normal combat" and generally people laying down effective tactics. For example, there is a pic of Churchill inspecting a Thompson:
The German media soon started calling him a Gangster. Gangsters were a very real threat during the 1920's (they were better armed than most of the police), the Sicilian mob who slaughtered policemen until Mussolini out gangstered the gangsters, there are still bandits who lurk around in Eastern Europe and the Mexican drug cartels are almost as well organized as the police and much better funded...
Also who the hell down voted the OP? Its a nice positive OP and its get down voted? What he hell?
Keep in mind that during the American Revolution, the British weren't too fond of American soldiers and militias who sniped from bushes and trees, taking out officers and ambushing their troops along roadways.... because they weren't fighting like men.
Keep in mind that fighting like men back then meant you stand in a straight line with your buddies and take pot shots at the enemy with muskets from a few dozen feet away.
Since the British had a bit more man power and such at their disposal, trying to fight the British on their terms would not have ended very well.
Same with the Russians against the Germans..... they had the man power, but the Germans had the tech, so you adjust your tactics in a way that exposes their weaknesses and gives you an advantage.
Survival of the fittest, anything goes.
Also, it can also be related to the Iraq and Afghanistan wars.... you have US/NATO forces with top of the line equipment, weapons, tanks and aircraft against a group of guys who are using dated weapons, 2nd hand AK47's, RPG's, IED's and the sort...... if they tried to fight US/NATO forces on US/NATO's playing field, they would have been wiped out years ago.
Instead, they expose our weaknesses in certain areas and take any opportunity they can to give us a bloody nose..... and we call them terrorists who use dirty and dishonorable tactics...... and whether or not they are, they keep their forces alive and continue to drag out these conflicts.... these tactics work for them, so they'll continue to use them.
The only real war in recent times that had all forces fighting on almost equal playing fields was WWI, and that ended up being a huge meat grinder that just went on and on and was a complete hell on earth for all that were involved in the conflict.
If a force sees a tactic that gives them an advantage over their enemy and can help prevent them from losing a lot of their men.... they'll take it.
If the enemy
isn't complaining about you and constantly calling you a terrorist, gangster or dishonorable due to losing a lot of their men.... then you're not doing it right.