In my opinion, this is splitting hairs. Yes, the student is not being directly penalized for absence, but the student is being penalized by being unavailable for something because of that absence. That’s close to the same thing.
I wonder whether there is a policy by which students who miss work (whether it’s participation or a pop quiz or something else) can make it up by doing a different kind of assignment. For example, when my kids were in school bands (which were credit courses with letter grades), participation in concerts was a required part of the course that counted toward the grade. However, if a student missed a concert because of illness or was unable to play because of an injury, the student could make up for it by preparing a written report on a topic related to music. Might there be similar policies school-wide to allow students to keep their grades up in spite of unavoidable absences?