The conversation seems to be veering into a game of semantics rather than addressing the biological complexity at hand.
The point isn’t about rigidly sticking to one label or another based on each individual interaction; it’s about acknowledging that the relationship can fluctuate based on various conditions. Therefore, there’s value in having a label that encapsulates this variability, like ‘facultative mutualism’.
‘Facultative mutualism’ doesn’t deny the presence of mutualistic or parasitic interactions but acknowledges that the relationship isn’t strictly one or the other. It can fluctuate between the two extremes based on different circumstances, and there’s utility in having a term that covers this variability.