Looks like you are open to learning the facts about Yogi Bhajan, 3HO and the business and yoga empire.
There are practicing Sikhs who contribute to this site. They can answer your questions about the Sikh religion. And they will point you to sources where you can learn more.
I'm not a Sikh. I do know that SikhiWiki, the internet link that you posted, is owned and operated by SikhNet.
It is a Yogi Bhajan entity and compromised as a result. It's a pretty good example of how this small group of dedicated Yogi Bhajan followers flies under the radar to push their agenda.
Bhajanists teach that "Sat Nam" basically means "God and me, me and God, are One", which is another Bhajanist mantra. This is a Hindu teaching and there is nothing wrong with Hinduism. Sikhs have no problem with Hinduism or any other religion or practice. Guru Nanak, the Creator of Sikhi taught that any religion or belief system, if practiced with love and humility, leads to Union (Yoga, in the highest sense of the word, not the physical exercise sense of the word).
Sikhs only complain about teaching Hinduism and calling it Sikhi - wearing Sikh turbans, claiming to be Singh and Kaur and Khalsa - while teaching and preaching Hinduism and New Age-ism.
First and foremost, Sikhs bow to no human. Sikhs only bow to their Guru which is a book. Reverence to ANY other teacher or belief or practice is counter to the Sikh Way. The Sikh Way doesn't claim to be the only Way, but Sikhs bow to no other authority than the Guru Granth. Even if Yogi Bhajan's teachings are wonderful (which I do not believe one bit) they can't be Sikh. Sikh's "spiritual teacher" and their "Yoga Master" and their best friend and companion is their scripture, the GURU GRANTH- none other.
Back to "Sat Nam" and what that means to Sikhs in contrast to what it means to Hindus.
First of all, this is a very advanced question, and I am a rank beginner Sikh. Sikhs who are far more enlightened and wise than I will be reading what I say, and I feel a bit silly...but hey, live and learn. If I make mistakes, I pray to get corrected because, again, I am a rank beginner student of Sikhi. I wasn't into the Sikh-part when I was a Bhajanist. I self identified as a Kundalini Yoga instructor.
I remember once sitting down to dinner at the Portland Ashram, chanting Saaaat Naaaaam over the food and everyone was really hungry, especially the men who had been doing physical labor and who were in their early twenties and thus still growing. We were just starting to eat when the phone rang. The person closest to the phone was one of the hungry young men. He picked up the receiver and said, "Sat Nam!" like Bhajanist's say as a greeting.
There was a pause as he listened, then he said, "Sat Nam means, Truth is who I am! Who the hell are you?"
This was funny, then and now, but for Sikhs, the True Naam isn't about little ol' me. The Hindu idea of "God and me, me and God, are One" kind of puts "me" and "God" at the same level, equaling ONE. Sikhs see the Sat Naam as the whole Universe, and our little puny lives and ego structures, our monkey minds, and our being primates on planet earth, and whether we are groovy or not, whether we are fat, or thin, lazy or active, sane, insane, live to age 5, 10, 50, 100, whether we experience whiz bang cosmic visions, or whether we don't - uh, it is just a small blip in the Infinity One's, Creator/Creation's life stories video collection.
Not saying that we/humans are not important, just saying that we are super finate, and we are no more important than anything else. We are puny and vastly limited compared to the Infinite ONE, the ALL-THAT-IS. Not forgetting THAT is key to the Sikh Way.
Thus, for Sikhs, Sat Naam is a name of the Divine One, and it is humble and good to leave "me" out of the equation.
As for Kundalini Yoga, this is what the Great Sikh Book Teacher, the Great Guru Granth, says about it:
“They read and contemplate scriptures, they practice the inner cleansing techniques of yoga, and control of the breath. But they cannot escape from the company of the five passions (lust, rage, greed, pride and attachment). They are increasingly bound to egotism.
This is not the way to meet the Supreme One and Only. I have performed these rituals so many times. Finally I collapsed, exhausted, at the door of my Creator and I prayed to the Beloved One, ‘Please, grant me a discerning intellect'”.
Guru Arjan, page 642