I assume this is a low level thing, since death ceases to be an issue at higher levels, at least for PCs, and healing magic as it is make it significantly less threatening for pcs with resources. So that angle or saving more lives IRL is meaningless when a spell or some GP can more or less totally invalidate that concern. Combat is sport for PCs, it is war for npcs generally

And no one will know about your surrender acceptance policy and such if all your foes die. Also the murderhobo adventure style where you are travelling from point a to b do not have to worry about reputation. Word cannot travel if there is no one to spread it.

If all your quests come from a patron, your instructions will be alive, alive if possible, or end threat by any means necessary so you know going in what you should do.

If you adventure from a central base but not at the behest of anyone, again your reputation does not matter.

Also unless in a very odd setting, at mid levels you have outstripped the ability of most normal humanoids to reliably be a threat. The foes you do face are much more likely to be either non-humanoid and/or have different societies and morals and goals than you and not respect whatever you and yours do.