Quoting Henrik Meinander in Finland in World War II: History, Memory, Interpretations, pages 74–6:
[T]he Finnish authorities had severe difficulties in feeding the population properly during the first winter of war and in keeping alive their Soviet prisoners‐of‐war and interned civilians. In this way, Finland had encountered a number of new difficulties in the ongoing war. In early January 1942, [Helsinki] received information via American diplomatic sources of the Soviet peace demands towards Finland, which would essentially have meant a return to the borderline of 1940.
Such a solution in that moment, however, would have been disastrous for Finland. Even if [an Axis] victory seemed less and less probable, Finland could not cut ties to [the Third Reich] without serious consequences for its already constrained defense capacity and food supply situation.^35^
The [Wehrmacht] still had a strong grip on the Baltic region and Scandinavia. Its troops in Northern Finland and around Leningrad showed no signs of weakness and were well equipped not only to support the Finnish front sector, but also to press [Helsinki] to continue the fight against the Soviet Union. In addition to that, Finland was heavily dependent on import of food supplies, artificial manure and many other necessities from [Axis]‐occupied Europe.
Obvious reasons for this were the permanent lack of labor force, the difficulties of reactivating agriculture in the recaptured Finnish Karelia and the geopolitically isolated location of Finland with all the import routes under [Fascist] control. On top of this came the unfavorable climate in 1941–43, which together with the other shortcomings decreased domestic grain production by over 35 percent from the prewar level.
Without the import of German produced artificial manure the fall would have been twice as great, which taken together meant that two‐thirds of the Finnish grain demand in 1941–44 was secured by [the Third Reich].^36^
[The Fascist bourgeoisie] naturally utilized this reliance to keep Finland in line. But at the same time they were themselves dependent on Finnish military support, which was essential for their control of the Baltic Sea and its coastal regions. The material support to the Finns was thus prioritized, in fact so highly that Finland was the only German ally that was allowed to buy German goods on credit.
This mutual dependency explains why President Ryti hardly ever found reason to emphasize to his German counterparts that Finland was fighting its separate war. Such a claim was equally problematic for public use in a domestic context, because it could easily have been interpreted by the [Fascists] as a sign of Finnish double‐dealing, and it was therefore used predominantly only in confidential communication with American, British or Swedish politicians, diplomats and journalists.^37^
(Emphasis added.)
Click here for events that happened today (December 30).
1884: Hideki Tōjō, Axis head of state, existed.
1935: The Regia Aeronautica Italiana bombed a Swedish Red Cross hospital the Fascist invasion of Ethiopia.
That’s a good question. Page 69:
— Henrik Meinader
So the likeliest explanation is that this was a means of ensuring that Finland would stay in the Fascist bourgeoisie’s orbit, because it was critical to the Fascist plan to destroy the Soviet Union.