The situations you described are different from your situation.

The co-workers are not in a relationship of suoervisor-supervisee. And in fact it can be a problem when one co-worker is promoted to supervisor, and she/he must now distance emotionally from those he/she is now supervising.

The other situations are permanent departures, the relationships were ending. In that situation, some limited emotional expression towards a supervisor can be acceptable.

Good job asking and exploring!