You make some good points.
I am of the opinion that as long as I live in a country with democratic (true) elections I will have to abide by the electoral results. If there are questions that I feel very strongly about then I will have to work to win that argument. But if there are things that go totally against all my moral convictions, then I will have to decide if I really can continue to live in a country like that.
As always we hope that we will never have to make such a decision, and in my case I have been lucky enough to not have had to do it - but, as you correctly point out, my tax money have often gone to uses which I have found reprehensible. Should I have lived up to my convictions and moved somewhere else? Or refused to pay taxes, with the legal effects that would have entailed? At least it has never amounted to questions of war or peace.
I think the argument about lives saved has been heard when discussing the bombs over Hiroshima and Nagasaki. However,gruesome the effects were, it seems quite clear that a full scale invasion off Japan would have cost many many more lives - and then the continuing barbarities of the Japanese in mainland Asia, which would have continued for another year, have as far as I know never been added to that equation.
It is inarguable to me that the “bombs” in Japan saved lives. It is also inarguable that the Russians heading towards Japan had a major impact on Japanese thinking. The Russian Army was a juggernaut at the end of WWII - possibly the biggest hammer in human history and it smashed everything in its path regardless of casualties. The Japanese military was a shell of its former self by that point with major logistical short-comings.
The end result of continuing the war would have resulted in much of Eastern Asia being in the USSR possibly including much of Japan. Stalin cared little about how many he lost - the UK/US populations were different.
The “bombs” were singular events that produced real horror, but people forget that the incendiary bombing of Japanese cities produced similar casualties and destruction minus the radiation sickness. Had we not decimated two cities we would have decimated them all with incendiaries and the subsequent starvation of Japan would have been the most horrendous thing of all. Japan, as we know it today, would not exist.
At the time, some argued that the bomb(s) should have been dropped on Tokyo killing the emperor or the Imperial Palace should have been bombed. The only man who could stop the war might have been killed and the likely reaction of Japan would have been horrific if that happened.
The argument about the “bombs” is always interesting but as it is also drowning in simplicity or singularity when it really must be weighed against many facts and likely outcomes.