The B-61 earth penetrating gravity bomb is a thermonuclear weapon, of variable yield. It's minimum yield is 0.3 kT. No typo.
All the targets you described are legitimate targets
Good. We're on the same page, there. And they're examples of "countervalue" targets regardless of whether we intend to destroy them with Tritonal or Tritium ...
and can be addressed using conventional precision weapons.
Not necessarily. That may depend very much on where geographically they're located, and how well they're hardened. Remember the German U-boat pens in WWII? We never did manage to defeat them. Their Me262 factory was similarly hardened. Maybe our current "Massive Ordnance Penetrator" would manage the job ... Certainly a W-88 would do the trick.
There have been lots of debate about our use of nuclear weapons on Japan - and I have gone back and forth on that subject myself at different times of my life
AS have I. I have no use for the deliberate killing of civilians for the sake of killing civilians. Arthur Harris was a monster. OTOH, both Nagasaki and Hiroshima contained legitimate targets, and the whole business of ending the war RIGHT NOW is not to be discounted. On the third hand, the death toll for the attacks on H & N were of medium size compared to contemporaneous firebomb raids. If H&N were atrocities, so were the firebomb raids on other cities.
but the moment we decided that the mass murder of innocents was justified, we lost part of our soul, losing our claim of being a Christian country.
I think that happened in 1865. The residents of Atlanta (or of the Shenandoan Valley) would probably agree.
By the time we killed all those people, we had already cut off Japan from oil and all other imports that could sustain further prosecution of the war and they were completely isolated. Their navy had ceased to exist and we could strike any part of Japan with impunity.
I know that we couldn't have invaded without horrific, even unsustainable casualties, and I know that there was stark fear that the Soviets were going to take over the attacks on Japan and seize territory - but we had other choices we could have made and didn't.
I'm not entirely sure that I equate Sherman with the heat, blast and radiation of our nuclear strikes but I'm with you that we lost our Christian identity along the way.