Viewers said the mental health specialist was robbed of the crown after she lost out to winner Rahul Mandal, despite winning the technical challenge.
Judge Prue Leith told her: "I think you would have been wise to do a different flavour because the ginger cake is so ginger-y the biscuit is a bit of disappointment after, it's a missed opportunity."
Paul Hollywood added: "The whole thing falls a little bit flat."
However viewers were irate she did not triumph, and one fan wrote on Twitter: "It's a FIX Justice for Kim-Joy. GET THE PITCHFORKS. NOW WE RIOT."
Another said: "What an absolute fix, he should have been out weeks ago, Kim-Joy was the most consistent all competition but lost because she had too many ginger elements??"
Another wrote: "Kim Joy was robbed. What a total fix," while another said: "Well, that's me done with Bake Off then. Has any contestant in the history of the show been as lucky as Rahul was a couple of weeks ago? I don't want to call it a fix but ... yeah, feels like a fix."
Another fan said: "I've literally just wasted 10 weeks of my life for that outcome."
Another wrote of Rahul: "Prue and Paul picked him as their favourite and the winner from day 1.
"Kim-Joy was consistent the whole time and won 2 out of 3 challenges this episode. He should've been out two weeks ago!"
She added: "Worst final ever!
However, other fans jumped to defend Rahul's win after seeing angry messages from other viewers.
One wrote: "Me reading all the tweets from people being mean to Rahul. I personally thought his showstopper looked amazing."
Another said: "Everyone calling #GBBOFinal a fix, it was filmed weeks ago, long before the public had chosen their favourites.
"Also, did any of you actually taste the bakes? Thought not!! But guess what, the judges did! Well done Rahul and all this years bakers."
Yet another wrote: "Rahul winning wasn't a fix, he was a clear winner, stop being so salty and bitter because your faves didn't win."