“there was a Toeles in telling his Chassidim about Notkin. Notkin offered the Rebbe tea that day and the Rebbe drank it so the Baal.Hatanya was teaching his Chassidim that even if you’re abused by your host you shpuld accept whst he offers.”
What to’eles is there in telling the person’s name. Wouldn’t it have been enough – if the story is true – to say that he was in the house of someone who abused him?
And from my reliable sources, that is the source of celebrating 20 Kislev. Not the printing of Tanya.