DY- rashi in RH i think on yud ches amud beis towards the bottom says that because klal yisroel was noheg chanuka for a long time and everyone was noheg to treat it as a quasi-y’t therefore it is kitorah. but the end of rashi says ulichain eino nachon livatlo, which would be mashma that this concept isnt mamash mamash. im remembering, not quoting.
Toi: Look at the Taz (quoted in the Beur Halachah) that says that Pirsumei Nisa is D’oraisa (I think it’s towards the beginning of Hilchos Channukah but I’m not positive). I think it explains the Rashi better. There’s a Rashi somewhere in Shas on the phrase Hanach Lahem… B’nei N’vi’im Heim that I think explains Minhag Yisrael Torah well (I’m either remembering a Rashi or a P’nei Moshe in Peah on the line about if you’re not positive about the Halachah then check out the Minhag).
I disagree with how its been told to you. It isn’t as cut and dried. But if you could accommodate a fresh name with a fresh start that will be the only one thereafter used, I’d be happy to comply with that.