You implied that this judge was discriminating because he rightfully told her to remove her burka.
He said that the judge was discriminting because the judge did *not* tell the woman she had to take it off by virtue of British Custom.
The judge should have said, "It's the British custom for people in court to be unmasked, therefore, because you're in a British court, you must unmak yourself".
Because the judge did *not* say that, it implies the judge was motivated by discrimination.