A US drone attack in Pakistan seems to have targeted enemies of the Pakistani government, rather than terrorists that might attack the US.

That does not necessarily make it worse, because I think that's the wrong question to ask.

If the government of Pakistan is fighting rebels on the battlefield and asks the US for military help in the form of drone bombers, providing that help would not be an outrage. It would be no more horrible to do this with drones than with crewed aircraft or an armored division. (Other questions would remain, such as whether such help in a given situation is necessary, justified, and wise policy.)

What makes the drones particularly threatening is that they are used for assassination away from battlefields.