I believe my firm is an exception, not at all typical. Both count when the faculty begins tallying up your ranking, which comes along later when you are looking for a position after graduation. Your professor keeps track of your participation at rallies right in front of the U.S. Interests Office. That affects your ranking directly, no matter how good your grades are. If your score is bad, you put yourself at a disadvantage when competing against others for a good position.
People tell a lot of nonsense.
I have never seen anybody thrown out of a job for missing a march. In my job people go because they want to. Of course going every day, that's tiring. Even the children know that. Or if a TV set is raffled, you are excluded.