It does strike me as odd, but not as odd as not going through with an appeal. At least with an appeal you have the dignity of refuting the, likely false, allegation and also have a chance to reveal what the ‘evidence’ is. Surrendering without a fight is not a good look imo.
Edit: while MY end of the following argument is cogent, out of respect for the accused I will point to new evidence that significantly discredits the IBA’s decision and competence. Their citing of an XY karyotype and/or excessive testosterone levels despite clearly stating testosterone and chromosome tests were NOT the initial reason for the DQs is simply baffling.