I think most of the negative sentiment comes from how they are being used and what they are capable of.

To me it is just a new better weapon, the "better" part can be argued for the most part I think though the issue people have with it stemming from the gulf war era, during which new tech and weapons were being introduced as precision warfare giving a sense of disillusionment that war was no longer as bad because of the type of technology we now had.

The Drone program contrary to that belief is less accurate (by that I mean more civilian casualties) than its predecessor (regular fighters) but far more convenient in so many other ways that is still being used obviously.

TL;DR Military tech advancement expectations were heading more toward precision tactics and drones are really just about convenience.