Acts of terror are commonly referred to in that manner because targeting civilians is the intention, with a desire to influence the population and politics.
Killing civilians accidentally is virtually guaranteed when engaging in military action.
So the tactics are extremely different in why they work, if they work at all. They are very different in the percentage of military vs civilians killed. They are very different in intention. The fact that they share some aspects in common doesn’t make them the same.
But you are correct, killing civilians with drones isn't much different compared to other acts of terror.