POW quotes an interesting document but misses out one small piece of information that sinks his whole argument
The Hague convention he quotes was a draft, it was never accepted
Draft Rules of Aerial Warfare, The Hague, February 1923
RULES OF AERIAL WARFARE
The Hague, February 1923
[Although drafted as the basis for an international treaty, the enactment of which was supported by the United States, these rules were never formally adopted]
So, as the rules were never adopted, how can they be used as evidence against Churchill? Unless he is supposed to be bound by agreements the country never even signed-up for.
I could, if I so wished, for example, find draft rules that would ban the use of artillery, tanks and the shot-gun, but because they were never implemented they are worthless, as is the draft convention POW quoted
You could try
Protection of Civilian Populations Against Bombing From the Air in Case of War, League of Nations, September 30, 1938
PROTECTION OF CIVILIAN POPULATIONS AGAINST BOMBING FROM THE AIR IN CASE OF WAR
Unanimous resolution of the League of Nations Assembly,
September 30, 1938.
Unfortunately Germany had withdrawn from the league by them......
And all that came out of that was:
Considering that the solution of this problem, which is of concern to all States, whether Members of the League of Nations or not, calls for technical investigation and thorough consideration;
Considering that the Bureau of the Conference for the Reduction and Limitation of Armaments is to meet in the near future and that it is for the Bureau to consider practical means of undertaking the necessary work under conditions most likely to lead to as general an agreement as possible:
So that never came into force either. You could try the following: definitions
(b) War Crimes: namely, violations of the laws or customs of war. Such violations shall include, but not be limited to, murder, ill-treatment or deportation to slave labour or for any other purpose of civilian population of or in occupied territory, murder or ill-treatment of prisoners of war or persons on the seas, killing of hostages, plunder of public or private property, wanton destruction of cities, towns, or villages, or devastation not justified by military necessity;
(c) Crimes against humanity: namely, murder, extermination, enslavement, deportation, and other inhumane acts committed against any civilian populations, before or during the war; or prosecutions on political, racial or religious grounds in execution of or in connection with any crime within the jurisdiction of the Tribunal, whether or not in violation of the domestic law of the country where perpetrated.
but that's drawn from
Nuremberg Principles, August 8, 1945
CHARTER OF THE INTERNATIONAL MILITARY TRIBUNAL
AUGUST 8, 1945
So its post-war and not retrospective it doesn’t count for the purposes of this, nor did Germany sign up for it. And anyway, with so many members objecting to anything to come out Nuremberg it would be hypocritical to latch onto this, especially as it would destroy all that ‘victors make the rules’ rhetoric that’s been flying about of late