I’d define an exploit as an interaction that was firstly not intended by developers but also unwanted by them as well.
In the linked thread they say that crits on sitting targets do not proc these affects. With that in mind, blizzard consciously made the decision to prevent this interaction. Trying to trick the game further to still get enrage procs from sit crits is likely STILL going against blizzard’s wishes, and should by all means be considered an exploit. It doesn’t matter how you cheat, you’re still cheating, no matter how much you try to pretty it up.