Drama aside this is about simple action economy and demanding services. A player that takes no effort to be tactical, heal up, take a break or do anything other than zerg in and die is demanding other people too spend actions to enable this behaviour. Thus costing them whatever other action they plan or like too do. This is selfish.
Clerics are effective healers, when one is around (s)he can heal you more effectively than you can. A byoh group with a healing cleric is simply optimizing action economy as well as being considerate.