What is the primary reason instant freezing upon exposure to space is a myth?

Answer

Heat transfer relies primarily on radiation, which is a relatively slow process

In a vacuum, heat cannot be conducted or convected away by air or water; the main mechanism for cooling is thermal radiation, which is slow compared to the onset of asphyxia.

What is the primary reason instant freezing upon exposure to space is a myth?
Spacedeathhumanexposurevacuum