Well, you put a moral judgement on a political decision.
Was Stalin cynical? Most probably, however the decision to halt (if it was a decision as the Russian claim they were at their logistical chain end so they couldn’t push forward –this wouldn’t explain the lack of support in ammunition and weapons/air support) was a pure political –perhaps immoral- decision.
From the Russian point of view, Poland was always an enemy.
From the Communist point of view, same: The Polish Dictator in charge prior 1939 was openly anti-communist and even supported Germany policy during the Spanish Civil War.
So Poland was anti-Stalin before Katyn (reason why Katyn happened, somewhere).
In term of politic and post war politic, and Stalin knew the war was won just didn’t know how much lands he would be able to do.
So resolving the Polish political future in letting the Germans to eradicate part of the Polish elite and in the same time denying to the anti-communist Partisan a propaganda victory in liberating their Capital was a typical communist decision.
What I learned in studying another Communist war (Indochina) is the Communists always favour the political (long term) effect even in a war. If a defeat gave them upper hand in the propaganda/media war, they will scarify men in order to achieve it.
If you judge Stalin’s decision from this, this decision makes sense.
Not a cynical decision but a plain battle field full of sense decision.

As the second point you can’t compare Democracy and Dictatorship. Of course no French Communist was deported or executed by the French Nationalist forces (even if some questions were raised on who betrayed Jean Moulin).
However, the idea to contain communism in France (and Italy) was always there.
And can I remind you what happened in Greece?
It took long time for Churchill to give weapons to Communist Tito instead of Mihailovic’s Cetniks (royalist) when it appear that the second one was more incline to wait in order to save civilian lives.
A I said Tito being a communist did scarify lives in order to gain political goals so he gave to Churchill was he wanted, at the price 100 civilians for one German soldiers killed (50 for one injured). It was implemented in October 1941 in Kragujevac.

The Kieffer Commando (Navy) was part of the British Commando No 10 was 174 men strong… It can hardly be seen as a French participation in the national territory liberation.
If you compare with Operation Anvil/Dragoon in August 1944, you understand that the decision to exclude French troops from the D-Day was indeed political.

About France treated as Occupied Territory, I’ve got this information in an interview I had with a French veteran when I was studying Indochina war. He was an officer in the French Corps Leger d’Intervention and met some US colleagues who show him their news shoulder insignia. It was the French Occupation Administration patch.

“Roosevelt’s feelings towards the French, at least regarding post-war talks, were chilly. While he’d harbored some distrust towards Great Britain, it was stronger with the French. When the American forces advanced into France, Roosevelt was sucked into the quagmire of French, wartime politics. Roosevelt and the US government had given backing to Vichy’s regime and refused to recognise the de Gaulle Free French movement. He saw him as someone who could raise the potential for a dictatorship in France. This strong dislike caused problems for the post-war planning talks. Without fully recognizing one of the main actors in the anti-Nazi movement, reaching a mutually agreed solution would be difficult to say the least. Indeed, Roosevelt would have preferred to keep de Gaulle from planning both the war and post-war plans. Requiring the French to disarm, in that case being treated similar to the Germans, made clear their place in the new world order that Roosevelt hoped to achieve; they would not be on the same level as the US, Great Britain, the Soviets, or China. France was to become another state in Europe that needed to be watched over by the stronger powers.”
In Tatiana McArthur, What Was Roosevelt’s “Vision of Europe”, November 30, 2009.