Why does its moisture saturation decrease at subzero air temperatures?

Everything is explained here very simply. At high temperatures, moisture evaporates, especially from rivers and other bodies of water. A striking example can still be called rain and how quickly the earth dries out after it. But the lower the temperature, the less moisture evaporates, the longer it takes to evaporate. But at a negative temperature, moisture does not evaporate at all, since water at such a temperature does not turn into steam, but crystallizes, turning into ice or snow, therefore there is a minimum of moisture in the air.