It is the absence of heat, as surely as darkness is the absence of light. The sun goes down at night and the Earth cools because there is no sun. We all know hate exists. It surrounds us. We experience it every day.
Hate is part of our primal nature.
A survival instinct, like hunger. Although we deny it. It's solid, it's there, and there's nothing we can do about it. Love is shapeless, an abstract, and only present part of the time-like cold. Allow me to explain.