Greatest Happiness Principle

According to John Stuart Mill's account of how we should live, only one simple rule must be followed: always maximize the good and minimize the bad. The good here refers to pleasure while suffering or pain is considered bad.

My problem with Mill's argument is in the numeric nature of how he depicts we should live. On one hand it can be seen as exact and precise, on the other I believe that we cease to become living sapient creatures and are reduced to simply numbers in a calculation, where sometimes the equation put into the system will always give an unfavorable response. For example, consider the case of the Nazi fanatic seeking out and actively killing Jews first brought up by Hare. On one side is the suffering of the Jewish people from being killed, on the other is the euphoria that the Nazi experiences for killing them. Furthermore, since he is a fanatic, his emotions of happiness are magnitudes above the suffering he inflicts upon his victims, and therefore Mill's principle will always be followed.

Also, in the case that one may consider that the Nazi's pleasures are of a lower order, consider the notion that the Nazi's greatest desires reside in exterminating Jews, again because he is a fanatic, and therefore such pleasures will always be considered of a higher order at least to the Nazi.