Good point but I would still prefer the term "mutually exclusive" to "incompossible" in that situation because it sounds more precise (even if the meaning is the same). My sensibilities may differ from yours.

Thus, I disagree that I had put it too strongly because it is a matter of choice not of fact-- I would reserve a word like incompossible for distinct realities and use something else for physics. I don't even know what a fermion is and if you told me two were incompossible I would probably smile and walk away.