Freezing ruptures cell walls in the food, so afterwards it spoils more rapidly than before freezing. The bacteria in the food will multiply while it is warm, and after refreezing, it can spoil during storage.
Freezing ruptures cell walls in the food, and the taste and texture decline. Refreezing ruptures more cell walls, and the taste gets worse. Rememeber that the food is never better than fresh.
The food may have alredy been frozen once, even when sold as fresh. I'm sorry to report this fact, but I have seen it happen. So don't freeze it unnecessarily after you buy iy.