Kids are penalized for excused school activities AND for taking IB/AP? That just doesn’t make sense.
As urged above, I would read the teacher’s and the school’s and the school district’s policies on absences and make ups. Read them carefully with your student. Make sure you really understand what is going on, where there are conflicts, etc. Are there mission statements or goals listed? Are there contradictions in how policies are applied?
Then I would get the student and if possible a group of similarly affected friends to go talk to the teacher, then the school admin, then on up the ladder. Coach them from the sidelines, but let them do it. If they don’t get satisfaction (I will leave the definition of that open), then you or better yet a group of parents should step in.
(As an aside, my kids had better results when they handled things on their own. One kid was in a class with a teacher who was lazy about making tests. She just got them off the internet and used them without vetting them. Often they didn’t line up with the material covered. The KIDS figured it out and went to her privately in a small group and discussed it. She stopped doing that. Another kid had scheduling issues. In a large school, guidance was slow about fixing them. Kid came up with a solution, went to counselor and presented it, she was happy to adopt it. Kid had gone around and received teacher permission for solution, etc.)