In answer to "Why else would you be feeding prisoners" are you assuming that players always want to recruit prisoners? I often sell prisoners who offer traits the colony doesnt need or have a 99% difficulty in recruiting, as the silver and slight negative mood buff to the colony outweighs keeping the prisoners. So why would I be wasting lavish meals on prisoners I intend to sell? Players may also be even more evil and use prisoners as live organ/limb donors when colonists get injured, so again why waste the best meals on them? Finally, when you release prisoners my understanding is players get the same positive factions relation bonus regardless of if the released prisoner has been well fed or given raw food, the bonus seems to only be affected if the released pawn is healthy or unhealthy. So again why would I be wasting my best food on prisoners who offer the same factions relations bonus regardless of how I fed them?
It is just so illogical for pawns to (by default) give best food to prisoners over colonists. The only reason to feed prisoners the best food is indeed if you want to charm and recruit them. Even then in my experience it seems to make little difference to the odds of recruiting prisoners if you do treat them well (e.g. with awesome rooms, great food, loads of art, etc) or if you treat them like worthless scum (e.g. no beds, small room, bad food, ugly environment, etc). If there is an increase in the recruitment probability by feeding them well it doesnt seem large enough bonus. [Note: I'm talking about my experience with A17 here, so not sure if any of this has been or will be addressed by A18.]
Players should have the option, like with medicine, to determine the maximum quality of food. That way if players do want to charm a particular prisoner they can turn this up, and if players do not want to recruit then equally they can turn the quality down.
