How would you enjoy the food when the one who prepared it got burnt by accident while preparing it? This proverb is similar to this situation. Milk comes from cattle, goats, or sheep. These animals are catered for by the shepherd. The welfare of the shepherd may have an impact on the satisfaction derived from these animals.
If the shepherd comes home in peace: meaning if the shepherd is well, having not suffered any harm, you will consume the milk without a heart full of sorrow.
This wisdom should be employed by leadership at all levels. The president, the government officials, etc. can enjoy their privileges well when the taxpayer, who funds the system, is well off. As leaders – government, management, CEOs, etc., enjoy their privileges, they should see to the welfare of the people on the ground working for them, by so doing they can enjoy their privileges without a guilty conscience, regret, or the disapproval of the people.
I stand to be corrected about the meaning of this proverb, but for now, this is how I understand it.