If god create all of us human being equally, then why we should worship different Gods and not the one?
When Hindu scriptures call God as "Ekam/One" it refers to God being "Anantam" or "Infinite" without a second infinity. Infinity cannot be two. Infinity is wholeness, everything that exist. Hence, there are no two infinities. That is what the scriptures mean when they say God is "Ekam".
Hence, this God, who is infinite and who alone exist, can manifest in infinite number of names and forms. Hence, through whatever name or form one worships, the worship ultimately reaches the same Essence, same God.
Hence, the sloka- "akasham patitam toyam yatah gacchati sagaram, sarva deva namaskaram, keshavam pratigachatti".
The reason people worship different forms of God, is because of different temperaments that people have. As one person is different from another person, their perception of God also differs.