The news of Sidney's plan to do an interview before her testimony reached the prosecutor's office. They knew this is not a good idea and they tried to convince Sidney not to give the interview so close to her testimony.
There is always a danger of her saying something contradictory to her initial statement or her testimony. Being on television "Live" is an anxiety-inducing task. She might slip up and mix up things and that could be used as evidence by the defense lawyers during the trial.
And the defense lawyers will question Sidney's motive in giving interviews. She does come off as someone who likes the limelight as a victim of abuse. The jurors might perceive her as a narcissist who is in an avenge mode rather than as someone pitiful.
The defense team will use that as an excuse to remove Sidney from testifying.
