If you think that terrorism was only a small part of the VC activities. I'll provide you some more cases.
In March 1961 the VC blew up a bus/truck carrying 20 school girls then opened fired upon the survivors. Killing 2 girls and wounding another 10.
In Feb 1962 VC threw grenades into a crowded movie theater near Can Tho, killing 108, 24 of them women and children.
In Oct 1963, VC set off a IED on a passenger buses killing 18, wounding 23.
In Feb 1965, VC blow up US barracks in Qui Nhon, killing 23.
In Oct 1965, VC plant bombs at Cong Hoa National Sports Stadium, one goes off killing 11, wounding 42.
In Dec 1965, VC blow up bomb in US base, killing 3 and wounding 172.
On Dec 14th 1967, Sagion reports in 1 week 232 civilians are killed by VC terrorist acts.
These are just a few of them randomly picked and not even based on time line.. the list is much much larger.
The fact standing national armies do it doesn't make it not terrorism. It's still terrorism. It's still targeting civilians, by the very definition which is given by those who call the Taliban terrorist, those actions by national armies is terrorism.
My point all along was there is no such thing as non-guerrilla acts, as in a Standing Army either acts ethically or doesn't. There is either conventional (two standing Armies shooting at each other) or unconventional (guerrilla warfare which includes terrorism). There is no gray. Only black and white. US Special Operations defines unconventional warfare as: consists of activities conducted to enable a resistance movement or insurgency to coerce, disrupt or overthrow an occupying power or government by operating through or with an underground, auxiliary and guerrilla force in a denied area.
Taliban doesn't have an Air Force, Helicopters, hundreds of tanks, and UAVs. Their ability consists of fighting the way of the VC, IRA, ETA, FARC, or all those Balkan "Militias" did. To the Taliban this is conventional warfare. To us, it's a foreign concept.