WTP I don’t know. All I know is that we always emphasise increasing light and positivity, fighting darkness with light etc. Yet regarding nittel its the exact opposite.
As is written in Hayom yom
“The reason for not studying Torah on nittel-night,1 I heard from my father, is to avoid adding vitality.
My father once said: Those diligent students who begrudge those eight hours and cannot tear themselves away from study – I am not fond of them. This (abstaining from study) applies only until midnight.”
My personal thoughts are as above (based on Tanyas explanation on how assur things are assur- tied down to klipa which is why they cannot be elevated by brachos etc.)
Also it would seem its the commemoration that matters not the actual date as like you said that wouldn’t apply.