Waheguruji ka khalsa waheguruji ki fateh,
Adding a little Sikh history to your subject of how these hindu ritual practices came into the sikh mould.
Actually the 140-150 years after Sri GuruGobind Singh Jee were tumultous for the SIkhs as they had to struggle to even survive. The Mughal era which was at it's demise left no stone's unturned to wipe the sikhs off the face of this planet. Prizes were announced for anyone who dared to bring a sikh-head. This resulted in the Sikhs to move to jungles,deserts etc and make a wandering living. IMAGINE THE TROUBLES THEY MUST HAVE GONE THROUGH.
Now the vacated Gurudwaras came into the handsof Samradayik & Nirmale Sadhus who had a respect for The Guru Granth Sahib and they looked after the Gurudwaras.
Then came the end of the Mughal empire and the SIkh Raj came into being in Punjab. Great Kings like Maharaja Ranjit SIngh and many others took special interest in improving the state of the Gurudwaras. A lot of land and money was entrusted to the Gurudwaras which made the Sadhus taking care of the Gurudwaras greedy, and the fall of character that accompanies greed reflected in them also. They became corrupt. Sikh rulers did not bothered to improve this internal state of the Gurudwaras.
Although these Sadhus used to respect the Granth and did it's prakash everyday, they were essentially HIndus and slowly Idols of our Gurus also began to be worshipped. All Hindu rituals related to Idol-worship started to be performed in the Gurudwaras. And as is the mannerism of these Pandits they managed to convince the ordinary sikh that these rituals were actually a part of our Guru's teachings.
No offence but that is the sole reason why even today all those useless rituals that our Guru's preached against, are being practiced by our Sikhs, and I think it is from this that several doubts have surfaced in our people, and this question put up by BAYANT is the result of that.
Please beware that our's is the simplest religion that ever existed on this planet. It only emphasizes simran as the path to achieving God. Everything else happening around us and every other belief is just a eye-wash. A mere source for greed to prosper.
Please forgive anything untoward.