I think Amber brought the story up again because she's running out of things to say and do on her vlogs. I suspect that the diet is over, but she is afraid of admitting to it yet.
If Becky is lying about having another job (I think she is), their only income is YT and YN. She got a few new subscribers due to her new diet, but if Amber can't produce evidence of weight lost, she'll lose them. She's already turning her attention to YN, which is something she does when she doesn't want to admit to something on YT.
She brought up the "rape" story again for pity points (and $$$ too), because people were beginning to get upset with her lack of loss, the admission of two binges in a week and photos of (what she claims to be) her weight. Unlike years past where she would re-introduce mukbangs under the guise of healthy eating, she's afraid to get demonetized due to TY's new policies.
In short, she's stuck with no content, tried to pull up a fast one to gain sympathy and it back fired on her.