I just remembered that the potion required Nano machines Equestria doesn't have in order to shape shift a human being, so I ask why doesn't the HLF just modify the potion to preserve more of a person so they can survive the background magic radiation?

7377552
Because in the author's point of view human beings deserve to die basically. And all their evil ways gone. In other words: free will. And become little more than a mindless drone.

Basically Superior Species trope. Resisting against your annihilation is somehow evil.

7377583
That's the meta answer though. I was asking for an in universe, one I intend to use for my own settings

7377649
Some works portray the HLF as extremists. It might be, in their view, treason against one's species to use the potion at all, even if it was modified.