Others are calling this out but they're not able to state why:

They're listed as adversaries and not enemies because aiding an enemy country suddenly unlocks a litany of other crimes.

Enemy is very specifically defined: https://www.law.cornell.edu/uscode/text/50/2204

Adversary is very specifically defined: https://www.ecfr.gov/current/title-15/subtitle-A/part-7/subp...