We always have, there's not really a case to be made for it being canon. If it were, that'd mean that:
- William Afton died two contradictory deaths
- There are two VR games (Ruin confirms there is only one)
- Michael survived the fire
- Baby survived the fire
- William survived the fire (Ruin basically confirmed this isn't the case)
- There is a brand new vengeful spirit named Andrew that was never mentioned prior the games
- The spirit in Golden Freddy doesn't exist and is merely Andrew. Andrew is just the FF version of Cassidy/TOYSNHK
- A mound of events that we would be hearing about (Sea Bonnies, Trash Afton, etc)
It would be an absolute mess to try and blend FF and the main timeline into one continuity. Tales from the Pizzaplex are canon (probably?), Fazbear Frights are not. The FNaF wiki doesn't consider them canon, no prominent internet theorists (FuhNaff, Matpat, Id's Fantasy,
RyeToast, etc) consider them canon (and they actually read the books lol, they would know), and the general consensus is that it's a different continuity like the novel trilogy
They're described as "hints to fill in the blanks" by Scott himself