but they apparently didn't test the idea of psychokinesis on pets because it'd generally be unimportant
Pets are also still not implemented.
Syrup and Oboro are special event reward (and could even act as test of how players would interact with them)
So the pets would have been a blind spot.
The "monster not resisting" requirement could have been there for other combination, such as successfully casting Sleep or Confuse (cost MP) to enemy monster before using Psychokinesis.
Unfortunately these kind of fictional games got too high degree of freedom.
Almost every interaction can be done, rather than being limited as "not supported" actions because the move, or how the system should response, is not coded