A person does not post on an anniversary and is judged to be distant. I propose to separate commemoration and obligation of online presence.
In the example, the memory is cultivated in a private gesture. The digital calendar facilitates reminders and shares, but does not establish the correct form of affection.
People in the same family can choose different ways. Respect also consists of not asking for a public proof of pain or fidelity every time a date comes back.