terrorism describes the infliction of civilian casualties meant to create a disproportionate climate of fear. By this definition, drones used in warfare are a form of terrorism.

Let's address that point. First, that's a convenient definition that erases the distinction between State and non-State violence which is critical to many people's formulations of what is and isn't permissible.

E.g I wouldn't tolerate my neighbor trying to search my house, but I would step aside for a police officer with a warrant.

Secondly, drone warfare isn't conducted primarily to kill civilian targets. Sure, bystanders do die in the process but there's never been an account of a US drone strike that was motivated by the desire to instill fear in civilians by maximizing civilian causalities.

Terrorists seek to maximize damage. States don't, or at least subject to some constraint. Carpet bombing is terrible on its own merits, but it's not akin to using nuclear / biological weapons.

In today's world we are not fighting wars in the traditional sense of defending ourselves against aggression.

We absolutely are fighting aggression. The Pulse Nightclub? The Twin Towers? Jihadists routinely declare war on America and work towards killing Americans. We're not fighting state actors (with the exception of ISIS) hence the term "asymmetric warfare".

Meanwhile, the US has typically funded various militant groups that oppose the regime, and now those groups are no longer needed. Some decide to seek power in the newly existing power vacuum. They will be branded as terrorists arbitrarily to suit the needs of the US PR campaign.

They were terrorists when we supported them, now they're just terrorists that bother us. Al Queda was a terrorist group when it fought the Soviets, it just became a problem for America when America became the new enemy.

The word terrorism is used to characterize a person or a set of beliefs or an organization as unworthy of respect and unworthy of humane treatment.

You're correct. And it's an important part of mutual radicalization, look at how quickly the left adopted very right wing thoughts after charlotesville. People were calling for punishing the terrorist's family, starting watch lists, and the importance of preemptive self-defense against terrorists.

Yet in the US we fail to recognize our drone strikes as the same tactic as suicide bombings, while we create untold pain and suffering abroad.

They're not the same tactic. The U.S is duty-bound to protect its citizens and the U.S citizens exchange obedience for protection, drone strikes are a mechanism of protecting U.S citizens, the legitimacy of the State depends on the U.S defeating its enemies. Sure, there are less violent ways of accomplishing the goal but that's for the U.S citizens and U.S influencers to decide.

Both of our major political parties strongly support the endless war and the endless killing and destruction of the political adversaries abroad who dare to try to control their own destinies and the destinies of their region.

Hardly. The U.S goes out of its way to support self-rule so long as the people are committed to liberal democracies. Look at all the aid the US dishes out and all the favorable treatment it gives fellow democracies.

What the U.S can't tolerate (and must never tolerate) is the formation of States (like ISIS) that dream of genocide for Americans or American interests or the defeat of freedom and liberty.