If you work on a smaller cluster in a research institution where in silico work represents only a small portion of the research output the management of the cluster will sometimes be subcontracted out to the general IT support shop. There an administrator - usually with not nearly enough experience will start receiving support requests from users with decades of unix experience which take hours of research to solve. Unable or unwilling (and because inactivity will look bad in the next meeting of department heads) the technician will start working on some "security" matter (so it sounds urgent and important). And this is how elimination of login nodes, cutting internet access to compute nodes, elimination of switches in the offices because they pose security risks (one might be able to connect an additional devices to the network) and implementation of 2FA on pubkey only login servers come in to existence.
Most of the cluster operators are wonderful. But a bad one can make a cluster significantly less useful.