The whole point of the military doing anything short of all out war is to scare an "enemy" into compliance through threat of violence. So it's not classified as terrorism for the same reason as lethal action by police is not murder. The blessing of the state changes its definition.
If you actively object the biggest military in the world, there is no safe place on this planet. A country that effectively uses black op sites to do torture on suspects that would be illegal back home, a country that actively uses a prison to indefinitely detain (and torture) suspects without any legal process (and so on and on... really, there are whole books about this), has absolutely 0 issues with bombing some enemy general. It can be even in the centre of Brusel for all they care, if the benefits outweigh the cons. If they kill 50 kids along, all they do is try to minimize media damage. Do you see many americans shedding tears over this? From outside its pretty hard to spot any, and anybody who cares knows how things are.
Let's not pretend wars are something nice, fair and some gentlemanly approach is applied. Almost anything that works will be used.
I doesn't matter what they do, commit war-crimes, liberate people from democracy(to free the people) and install dictators, fund terrorists, lie to the international community about wars, kill people in embassies, it doesn't matter. It is you who are at fault, for not being able to understand their deeper moral motives.
Everything that the enemy does, that is either illegal or it's just lies and propaganda to improve their image. They can do nothing right.
Now, With this context you can understand very clearly how to think and feel about who the terrorists are and who the bad guys are.
Note the statistics here [0] - of course the numbers are very fuzzy but at the worst case scenario it's 1:2.5 civilians: military targets. So for every 2.5 military targets, 1 civilian. That fits the bill for extreme and indiscriminate.
[0] https://en.m.wikipedia.org/wiki/Drone_strikes_in_Pakistan
Also, one needs to indicate the difference between e.g. a hospital building acting as nothing but a hospital, and one that has been evacuated of patients and used as a militant staging post.
Too long, didn't listen: If you rob with a little ship, you're a "pirate", but if you steal with a big fleet, thou art "emperor".