It should be noted that the terms being used here are often flat-out wrong! Drying and curing are being mixed-up.
Freeze-drying is just that, drying, dehydration of water and other relatively volatile liquids. At freezing temperatures, there is no enzymatic action, microbial growth, much less oxidation and other chemical reactions, etc. But these things - natural enzyme activity, microbial growth and fermentation, oxidation and other natural breakdown of chlorophyll and other components are critical parts of "curing."
Curing involves all kinds of chemical and physical changes in the plant material, most of which are due to residual enzyme and microbial fermentation, while freeze-drying just involves dehydration (which has its own physical effects) with none of the other biological and chemical activity.