According to LDS teaching, why should we worship this God? This question discusses the LDS teaching that

“As man now is, God once was; as God is now man may be.” ( The Teachings of Lorenzo Snow, ed. Clyde J. Williams [1984], 1.)

The teaching is partially motivated by the passage from John5:19,

So Jesus said to them, “Truly, truly, I say to you, the Son can do nothing of his own accord, but only what he sees the Father doing. For whatever the Father does, that the Son does likewise.

Joseph Smith himself said:

As the Father hath power in Himself, so hath the Son power in Himself, to lay down His life and take it again, so He has a body of His own. The Son doeth what He hath seen the Father do: then the Father hath some day laid down His life and taken it again
-- History of the Church 5:426
I want you to pay particular attention to what I am saying. Jesus said that the Father wrought precisely in the same way as His Father had done before Him. As the Father had done before? He laid down His life, and took it up the same as His Father had done before. He did as He was sent, to lay down His life and take it up again; and then was committed unto Him the keys. I know it is good reasoning.
-- History of the Church 6:373

From LDS.org:

The Prophet Joseph Smith himself publicly taught the doctrine the following year, 1844, during a funeral sermon of Elder King Follett: “God himself was once as we are now, and is an exalted man, and sits enthroned in yonder heavens! … It is the first principle of the Gospel to know for a certainty the Character of God, and to know that we may converse with him as one man converses with another, and that he was once a man like us; yea, that God himself, the Father of us all, dwelt on an earth, the same as Jesus Christ himself did.”

As to this notion in the modern LDS church, President of the Quorum of the Twelve Apostles Joseph Fielding Smith said in an address in 1971:

“This is a doctrine which delighted President Snow, as it does all of us. Early in his ministry he received by direct, personal revelation the knowledge that (in the Prophet Joseph Smith’s language), ‘God himself was once as we are now, and is an exalted man, and sits enthroned in yonder heavens,’ and that men ‘have got to learn how to be Gods … the same as all Gods have done before.’

So, in summary:

God the Father was once a man who became exalted to Godhood, and created us in his own creation.
The man who is exalted now will be God of his own creation, as God is God of this one.
All Gods have endured this process.

My question is:
If God was once a man who had a God of his own, then from a Mormon perspective, why don't we worship the God of that previous Earth who created the man that is now our God, and who therefore is the God of our God, instead the God who created the Earth we inhabit? In other words, is the Creator of our Creator not also worthy of our worship?

Edit re. close vote due to duplicate question: I'm not asking about monotheism or polytheism, or asking Mormons to reconcile the claim with monotheism. I'm simply asking why we are directed to worship this God in particular, and not the God who created the Earth from which he was exalted. These are clearly very different questions.
Consider any reason a Christian would worship God:


He created us.
He (through his Son) saved us.
He has commanded that we worship him and pray to him in the name of Jesus Christ.
We know and love him.
We fear the consequences of not reverencing him.


All apply, and specifically to God.