Hitler suffered acutely from meteorism; perhaps he did not suffer so acutely as those around him, since meteorism is uncontrolled farting, a condition exacerbated by Hitler's strictly vegetarian diet.
The rationale for loving others is the recognition of the simple fact that every living being has the same right to and the same desire for happiness, and not suffering, and the consideration that you as one individual are one life unit as compared with the mulititude of others in their ceaseless quest for happiness.
When one drives away the negligent through vigilance, he climbs the heights of wisdom, and can see the suffering masses. Serene, you look upon the lost like one that stands on a mountain sees those that stand upon the plain.
Whenever we feel that we are definitely right, so much so that we refuse to open up to anything or anybody else, right there we are wrong. It becomes wrong view. When suffering arises, where does it arise from? The cause is wrong view, the fruit of that being suffering. If it was right view it wouldn't cause suffering.