This definition only reinforces the parent's point. What it rules out as "not terrorism" is regular organized crime, which isn't too much into bombings anyway. Bombs are almost never used without a political/ideological agenda, because they're too expensive and require too much coordination to make, maintain and deploy.
You're wrong, all those WWII resistance fighters were by definition terrorists to germans/japanese. Its just that US marketing over-used the term in past decade and a half to label anybody inconvenient as a justified target for extermination because 'national security'
Except that to some extent, they do. When my country was occupied by the Nazi Germany, people who fought back were called freedom fighters by us. They were called terrorists by the Nazis.
I think terrorism is killing random members of a population to scare the others into some political or ideological change. It wouldn't count if it was targeted at fighters and civilians got killed by accident.
That sounds like a reasonable definition. But how would this definition qualify the Taliban attacks on military bases and police stations in Afghanistan?
