Wiking,
You have a more hopeful view of human nature than I do, I suppose. Given what the Turks did to the Armenians (at roughly the same time, historically speaking), I am not as confident as you are that there were all that many restraints on the our behavior regarding civilians prior to WWII. The question may have been one of technological limitations (i.e. we simply didn't have the tools for truly awful mass slaughter), but I am not sure that if some of those tools had been in our hands (particularly on the Eastern Front) in WWI, that we wouldn't have performed just as badly...
And thanks again for that reference...I just ordered the book!
I am referring to the Western Front only. In the Middle East, on the Eastern Front, and even Italian Front poor treatment of prisoners and violence against civilians occurred, probably the worst on the Eastern Front. That said, it wasn't as bad as WW2, because so many taboos had yet to be broken. WW1 radicalized everyone to a degree and it took time and ideology to break down these taboos. Even in WW2 massive civilian bombing happened only after certain events in the west, but started immediately in the East. During WW1 in the west, attacks on civilians started after 1914. Yes there were atrocities in Belgium and France related to the Franc-Tireurs, but these were generally isolated incidents meant to restore order (or such was the perception of the Germans at the time) and a hold over from the Franco-Prussian war.
Use of new weapons of 'mass destruction' were not used against civilians on any front though OTL, which makes me wonder why it would happen here if rockets are around. It was not a desperation issue though, because both sides had plenty of opportunities to do it in the same situations that would occur here too, but did not. Call it strangelove or whatever else, but there was something that caused all sides to hold back from using chemical and biological weapons against civilians in WW1. Perhaps it was a means to retain
some humanity during the war, I don't know.
All I know is that there was
massive outrage when the Germans first used gas and a lot of effort went into moralizing and legal arguments for it. The Germans even refused to use the more effective projectile means of delivery because the word of the law forbid it. Instead they used a much more dangerous (to the user) delivery method of digging gas tanks into the ground and letting the wind blow the resulting cloud of gas over to the enemy side.
Franz Josef refused to allow its use at all by his army, even with great pressure exerted by the Germans to use it.
There was a major mental block then against using these weapons in the mind of the public and even the military (there was much disagreement about starting to use gas on the German side). The creation of rockets won't make gas usage happen any earlier, nor will it change the perceptions of using it. No one was ready yet to use it on civilians, nor were they in WW2. Its just not going to happen because humanity gets hung up on some things, but not others. Chemical warfare against civilians is one such hang up, as is biowarfare, at least in the modern era in the West. Who knows whether it will remain that way, but for the sake of our discussion, no power in WW1 will do it.
Edit:
Would they be accurate enough to aim them at port facilities, major railroad nexi, and major manufacturing centers with some non-negligible chance of success?
Depending on the advancement of research, there could be a ballistic missile campaign as part of the strategic bombing of Britain in WW1. Use against Dover, Calais, Dunkirk or any channel port in range (depending on what is possible) could happen. Interesting to think about what effect that would have on the war and supply situation. Massed rockets against Ypres in conjunction with a gas attack in 1915 perhaps?