I understand what you are saying. But I don't have Moses' understanding of G-d either. I don't even have my own Rabbi's understanding of G-d, let alone Moses. That doesn't mean we don't worship the same G-d. And let's say I thought that it was permitted for Jews to eat un-tithed grain grown in Israel and I thought G-d only sent 9 plagues. Does that mean, since I'm an ignoramus I'm not worshiping the same G-d as learned Jews? There are certain common denominators, that - so long as they're met - there is leeway from person to person with regards to their belief or understanding. It has to be that way.
I agree there can be leeway, which is what I argued above, there can be minor differences like disagreement in dietary habits or interpretations. However, I am sure you can agree this leeway cannot be infinite, there has to be a point of demarcation or a line that once you have crossed you can no longer be within that tradition of thought. This is what I have attempted to argue above with Mormonism. I have called out the fallacy as a slippery slope that just because we can allow some minor differences between sects of a religion, then are forced to allow major differences of a divergent religion still claiming to be in that lineage.
Let's say I have two daughters. They hear me say something and one assumes I said X and the other assumes I said Y. Does that mean my daughters believe in two different fathers? Let's say I actually did say X. Does that mean the daughter that thinks I said Y believes in a father that doesn't exist?
Its kind of the same thing here. Muslims believe that G-d spoke to Muhammad, Jews believe He didn't. But we both intend the same G-d.
The problem with this analogy is that in this case the two daughters have actually heard you and you know that you exist and you exist as a flesh and blood person as they do to too. However, 99.999% of religious believers do not know of God's existence, have not heard God or seen God, but believe in God as
faith based on the revelation of another who claims to have seen or heard him or had messengers like angels. Hence, they work with a borrowed understanding of God. Those working in the tradition of Moses, work with Moses's understanding of God and within those boundaries(with some leeway) Hence, they are worshipping Moses understanding of God. According to that understanding, Jews are the chosen people.
Those working in the tradition of Mohammed's understanding of God, work with Mohammed's understanding of God and within those boundaries(with some leeway) Hence, they are worshipping Mohammed understanding of God. According to that understanding, Muslims are God's chosen people and he hates Jews.
Now there are four ways to approach this
1. Moses heard it right, and hence the correct understanding
2. Mohammed heard it right, hence has the correct understanding
3. Both heard it wrong, hence both have the wrong understanding
4. There is no God in the first place, they made it up
As followers of either Moses, Mohammed or Jesus whatever we know of "God" is based on the attributes and narratives they gave. Hence, we cannot speak of "God" as separate from the attributes and narratives. Whatever God we hear is somebodies revelation.
We Hindus also have our own understanding of God and ours is revealed through our equivalent of prophets or Rishis. They obtained it not through God coming in person to them, or an angel or messenger, but through meditation they experienced God within themselves. Hence, we inherit a very different understanding of God, as a pure or highest state of consciousness/Self(God within) and thus we describe God as an abstract entity as the substratum of existence, consciousness and bliss. However, the distinction here these are not attributes of God, but the rather the nature of God. Attributes and narratives would be saying stuff like "God has a son, a daughter, God came and spoke this, God lives in heaven, God cried, God laughed" As attributes and narratives depend on posteriori knowledge, that is knowledge from experience we gain from the 5 senses and mind, none of these finite categories can capture God. As God is infinite and absolute existence that precedes us and will be there after us too, nothing that we attribute to God is valid. It is at best an image, symbol or tool that reminds us of God(proper) but taking it be God, would be like taking the picture of the moon to be the moon. Therefore, we Hindus allow infinite images of God, but never mistake the image to be God itself.