You’re saying there’s a meaningful difference between being shot in the head and having a bomb dropped on you.
Those are the words of a coward who thinks that it’s somehow better to kill people indiscriminately from a distance than to destroy them one at a time in person. I very much doubt the dead make any such distinction - nor would you, if you watched your family burn to death trapped in the shattered rubble of their own home.
Civilians are not military assets. Every international treaty recognizes this fact, and it is a war crime to target civilians. You may not intentionally kill non-combatants. That includes not only civilians, but also medical services such as the Red Cross and even neutral military forces within an active war zone.
There are even stipulations within international law addressing the concern of unscrupulous armies using such non-combatants as “human shields”. You may not conceal military assets as civilian, medical, or neutral assets. This is why soldiers wear uniforms, and why you can’t paint a medical cross on your munitions bunker. All such behaviors are war crimes.
Functionally speaking, there is no difference between beheading a city worth of civilians and bombing them - except that in the case of beheading, civilians can actually choose to resist their murderers. You can fight, flee from, or even engage in diplomacy with soldiers on the ground. Bombs cannot be fought, cannot be outrun, and cannot be reasoned with.
They also kill many, many more people with far, far less difficulty than ground forces ever could. They destroy infrastructure, causing indirect casualties long after the attack has concluded. Ground forces place themselves directly into the line of fire in order to kill, but bombs are inherently disposeable, unlike soldiers.
Ground forces also have consciences, and can choose to discriminate in their targets, selectively avoiding killing those they do not wish to, or even actively disobeying orders. Bombs are unthinking, unknowing, unfeeling - they cannot be swayed by pity, cannot choose whom they kill, and cannot disobey orders.
There is at least a chance that a soldier will spare a lost child that they find in their path, but a bomb will rip them limb from limb every time.
Despite your claims, US troops have historically engaged in mass executions of civilians. Notable examples are easily found in the American Civil War, the Korean War, the Vietnam War, the Afghanistan War, and the Iraq War.
Additionally, the United States is the only nation in history to have deployed nuclear weapons in wartime, and the targets of Hiroshima and Nagasaki were specifically chosen as civilian targets devoid of military value. To claim that these bombings were anything other than “mass executions of civilians” is delusional.
I’m just going to come out and say it: you are wrong.
The United States is not a shining beacon of purity and righteousness. Its hands are as bloody as anyone elses. The US military has repeatedly, knowingly, and fully intentionally committed atrocities, conducted mass executions of civilians, and engaged in breaches of international treaty and war crimes. And they have never been held accountable for these actions.