I think it's to do with absence.
For example -- a simple though perhaps not very deep analogy -- you might as well equally ask, "How is it possible to hear silence, when ears hear noise or sound, and silence is an absence of sound?"
The Brahmana Sutta (SN 51.15) suggests it's a case of, "Having arrived, the corresponding desire/energy/idea is faded away."
A way in which one arrives is described in SN 41.5:
Greed, hate, and delusion are bonds. A mendicant who has ended the defilements has given these up, cut them off at the root, made them like a palm stump, and obliterated them, so they are unable to arise in the future. That’s why a mendicant who has ended the defilements is called ‘unbound’ ('abandhana').
Training yourself not to get angry and so on, to do away with the habits and thought processes and attitudes from which anger arises (see also What is effluent?) -- that seems to me do-able even if not everybody does it, I don't see why it should be theoretically or logically impossible -- and see plenty of people, especially adults, perhaps it's even the norm, that people appear to be at least partially successful.
One more thing, consider doing something wrong as the result of certain conditions. Conversely if you don't do something wrong, then that (non-existent) action isn't conditioned, its non-existence isn't impermanent.