I believe you just shot yourself in the foot, because I haven't discussed Hellenic polytheism once, and that you think my discussion has had a thing to do with it rather shows where you're falling short.
I'm not arguing in support of polytheism, I'm arguing that your argument is invalid because perception of deity varies. Thus, monotheism of the type you're describing and polytheism are only two ways of viewing the same whole. Qabalistically speaking, at any point on the Tree, you can see that as being the source of the rest of the Tree, because everything contains the image (or DNA, to relate it to modern science) of everything else. Observe my signature - I am created in the image of G-d, with all the associated rights and responsibilities. That includes that I can be the prophet of my own religion, and I am. I just don't expect anyone to agree with me. However, as I'm human, I'm rather terrestrial rather than celestial or aethyric - so I'd be Malkuth; the crystallization of deity. But, Malkuth is the
direct reflection of Kether, so I look exactly like G-d. So do you, actually..."Love your neighbor as yourself, and love G-d before all things," and you can't do one without doing the other. I'm totally fine with being saved by Jesus, and Mithra, and Lugh, and Dionysus, and Balder, etc. etc. But I'm way happier when I place my trust in She who Rules Saturn and Binah.
The archetypal quadrinity is the sensible explanation of Christian doctrine, and why I'm ultimately pagan - and a Thelemite at that. The tetragrammaton (or, rather, one of them) is YHVH. "Yod" is, by gematria, the supreme creative force - the hand. It's kind of masculine, but ultimately gender neutral. When it links with "Heh Premiere" - the window or opening (koff...there's a double entendre here) - the result is "Vav." "Vav" means "pin", and there's another double entendre there, which when it links back up with Heh Premiere yields Heh Finale, which is another...opening.
Interestingly, "Heh" implies the opening you wouldn't normally go through. "Daleth" is a door...just sayin', G-d is kinky.
So, that'd be the Father, the Mother, the Son, and the Daughter. Incestuous? Yes, but that was at one time a sign of royalty. Christianity lacks the Daughter, unless one considers the Church to be that Daughter. However, also YHVH is only one four-letter name for deity...AShRH is another one (Air feeds Holy Fire of the Sun that lights the Window), LYLTh would be another (The Goad in the Hand drives the Hand to the Cross), or LYLT (The Goad in the Hand drives the Hand to the Serpent), ALLA, etc., etc.
But none of that really matters, because you're totally right that - in monotheism - your view is correct. In polytheism, your view is incorrect. Unless you have perfect knowledge of G-d, then you have no idea if you're 100% correct, and thus cannot say that others are incorrect...only that you feel they are. Their worldview is quite different, and the argument is totally pointless unless you can fully grasp and identify with their worldview...in which case, you would see their point of view.
Everyone in this thread is both totally correct, and completely wrong, and that's totally fine.
/drunk posting...and you can tell I did grad school, because my spelling is perfect while tipsy. Win.