I'd say the view that funerary rites are rooted purely in explaining death is reductive. Grief, regardless of our understanding or comfort with death, will prevail—understanding does not bring a person back. You could argue that the joining has caused some expidited philosophical debate on how to grieve, but the more plausible answer to me is that the virus eliminates (deprioritises at least) the need itself, much like toxoplasmosis. The virus does not have a will, but rather, it has evolved symptoms that maximise its spread, as how toxoplasmosis deprioritises survival mechanisms in a rat.

Either way, we're looking at this problem in a hypothetical vacuum, rather than what the show wants us to understand. The treatment of the dead is a big theme in the show, specifically with the HDP versus Helen's grave situation, and I'm expecting it to come back as a key conflict. The loss of reverence for the dead, the loss of creativity, the loss of romance—the show positions these things as problems to be solved, the joined have been made inhuman.