When admins clicked "Un-Enroll" in ILC Activity layout, this action will also delete or remove the learners' enrollment records in all sessions within the ILC course. If the admins would like to just remove the learner's one specific session of ILC Course, they have to look for the required session and remove that session via "Edit Activity".
From an admin’s and workflow perspective, it would be much convenient for the admins to directly un-enroll the leaners in a specific session of an ILC Course when the admins mark attendance via ILC Activity layout.
If the admins can only delete a specific session through the below method, it would be creating more step/workflow for the admins to look for the right session information in order to update the attendance and higher risk is also created as the admins may delete the wrong session information.