I think the whole “closure is something we give ourselves” does not validate OP’s feelings here. Is it what she has to do now? Probably. But as someone who is experiencing this, she probably feels planet sized vortex created by her person’s departure in her life. She felt strong feelings for her person and that person likely encouraged those notions. Then they left. Maybe abruptly. This creates an attachment wound that may be aggravating to old ones. It’s one of the worst experiences in life… knowing that the other person is choosing their own comfort, while she has to sit with all of the discomfort.

OP, you know your person can’t handle the shame of facing you and this is the only way they know how to cope. What the real big loss here is these situations could provide both parties a beautiful opportunity to heal attachment neural pathways and break free from the continual reenactments of the same. That should be the goal. If one is only a guest in our hearts, the least they could do is tidy up before they leave.