Intolerance lies at the core of evil.
Not the intolerance that results from any threat or danger.
Not the intolerance that arises from negative experience.
Just intolerance of another being who dares to exist, who dares to diminish the space in the universe left for you.
Intolerance without cause.
It is so deep within us, because every human being secretly desires the entire universe to himself.
Our only way out is to learn compassion without cause. To care for each other simply because the other exists.
Space versus Time
When we are intolerant of others taking space, it is our animal nature displaying itself; just watch nature shows and / or observe the wildest animals in nature.
But it is not enough to be tolerant with space; it is when we are generous with our time, we are at our best, as human beings, transcending space. I think this is part of what the Rebbe calls Compassion, but I might be mistaken...