Right. If they trespassed her for a t-shirt, it would have been because of the t-shirt.
In this case, it was because of the mask rule bullshit. BECAUSE OF THE MASK RULE.
And you think the mask rule is BS. The administration does not. That is why we have courts to decide between the constitution, the law and the two opinions.
No need to try and fight the battle there at the school. Take the notice, leave, and file a lawsuit. Get your day in court.