The foundational and fundamental understanding of God is that He is distinct in all ways to everything else and therefore He cannot be compared to anything else whatsoever. Hence He is Incomparable. Everything about God is Incomparable. Whatever/Everything that is about God, is never about anything else.
To say and understand this is to know that such a nature is befitting of the Majesty, Excellence and Glory of God and directly to know God Himself.
This in turn extends to our relationship and association with God. That whatever we do (regarding ourselves with respect)to God - whatever happens between us and God, does not elsewhere.(which is why there is also nothing "outside" of God - this is also an understanding of metaphysical reality itself. What is meant here is that God is the Creator and whatever proceeds from Him is creation, and there is no created thing or realm which God can be removed from)
We are the cohorts of God, and the interaction that takes place amongst ourselves, although made up of differences, is not entirely distinct, infact not even distinct in an actual sense, as absolute distinction alone is that of God, the world of difference actually is God's creativity and power, and God maintains His Exalted state with respect to anything of anykind, which is something that we cannot(unless we embark on the of Yoga - even then even the perfected Sages are not Co-Equals to God, the understanding here is that equanimity can only be achieved by one devoted to God and sees His Supremacy over all things else, so this is a further understanding for one engaging with greater dedication at a more advanced level, we have to "try" and "strive" and all the while God would direct and guide us, so again here it is just about being a better servant to God, and that is based upon your own standards, the state of equanimity which would be achieved then too is not "being like how God is", its the state of creation being closest to its Creator on its own accord, God is Intimate with everything/everyone always)
How is Hinduism "incomparable" ? Hinduism is not incomparable in the sense God is. Hinduism is the path to God, the Incomparable One, hence it derives its incomparability.
An "example"(so to speak) is the worship of God, which is tenet/practice.
Worship should only be to God.
Why is God alone worthy of worship? Because God is distinct? But if so, that means God is distinct only what, right? What has worship got to do with anything? God doesnt lose his distinctness if worship by us is directed elsewhere, right?
That is right. This is where the subsequent understanding comes.(I will get to this later) We can choose to worship anything besides God, but that doesnt mean its correct, the fact that we have a choice means that we have freedom, but freedom is not without consequences(and I dont mean Hell here), and the reality that we can seek to not worship God shows(to us) that God is not intent on you worshipping Him. It is not that He "cannot", even if God made you only worship Him(without a choice), it wouldnt mean that He got what He wants more, everything is done in God's way(including our not worshipping Him). The only way is that of God, no matter what you do, its God who is actually under control. To feel this is worship.
Now getting back to the subsequent understanding.
God's incomparability is that God is unlike anything - He is distinct from all else, and only He is that way, and within this is the natural understanding that Brahman is one without a second, one without a part, one without a kind, one in a way that is uncompromising, beyond numbers, simply the Supreme One, the Absolute, or God/Brahman.
God remains Incomparable no matter what He does.
What we do towards Him, where we honour Him (be it speaking of Him, praising of Him - when you speak of God, it is by default a praise, such is the Glory of God, God is Great and His Greatness is Infinite, this is the truth about the nature of God, saying this alone is also a praise -, or worshipping Him) should not be done to something else. Or else its delusional.
Speaking about God, we say God is Omniscient. To say something else, like for example a cup is Omniscient, is on our part our own delusion, as it is false, and we are the only stupid ones here, God remains to be the only entity which is Omniscient.
Likeso, action towards God that is (physical)worship, should be directed towards God alone.
One can speak about God, and not understand. One can bow down and not understand. The root of worship is understanding, and that requires the focus of the mind on God.
Knowing God and accepting Him for who He is, and feeling about Him which is in a certain way unlike anything else, is because the person who is God is distinct/unique.
The basic following of Hinduism is this. Worshipping God (according to how God sees it fit, and doing it the proper, acceptable way).
Subordination without question/hesitation is worship. And subordination by all costs towards someone else is only something apart from God, that we can do to Sages. Because Sages are servants of God who are greater than us (better in their servitude, who can even communicate directly with God).
They(Sages) verbally transmitted to us the truth they had ability to receive i.e Vedas. And Vedas are Holy.
A Sage may ask of you to do something. And this may not be directly related to his work on behalf of God. Still you must do it. Simply because he is a Sage.
Moreso then are the Vedas, which are Holy, thus in this way too they are Infallible/Uncontestable. The value of the verse of the Veda does not rest on the Sage who revealed it, but the verse itself, the truth that it is. The Sage rose to prominance because of the verse.
The reason behind subordinance to a Sage is not because of his own nature, but because he is more close to God than you are/he is of a higher "spiritual rank". And serving him only cleanses your sins and association with him in anyway is a blessing.
And unlike other "ranks" and "authorities", Sages do not take delight in exercising their authority, they have handed their egos over to God, and do whatever God commands them to, which is why they are fit for the task.
Similarly the religion of the Vedas, that is Hinduism, according to Indian cultural context, because India is the land of the Sages, is incomparable, because its about God.
Hinduism isnt God. Hinduism is the religion of God, as followed and taught by the Sages. So Hinduism isnt Incomparable the way God is but through its relation to God, that of being the religion.