Source? Debating the definitions of words is often silly, but I think it's worth pointing out that 1) the definition of "terrorism" isn't broadly agreed upon, and 2) the definition you're using is more narrow than peoples'. The definition that searching google gives is "the use of violence and intimidation in the pursuit of political aims", which drone attacks certainly fit into.
More generally, it seems that condemning vague things like "torture" and "terrorism" accomplishes very little, because people will simply use different definitions of the terms to skirt the condemnation. So we have to condemn specific things that are wrong, like waterboarding and drone strikes.