AAQ,
The poshut pshat is like the Maharsha and Meiri that the gemorrah is not referring to what we call the notzrim but another group/ideology that was already around by bayis rishon.
Why is that so shver?
It obviously cannot be referring to people who only appeared at the end of Bayis Sheni to explain why the maamados bizman habayis didn’t fast on Sunday.
As an aside, the blatt at the end of Maseches Taanis have many shinui girsaos – even a shinuy girsah that changes the word from Assur to Mutar.