What is the story behind Mohinder Singh SDO? as far as i know he was a chardhi kala Gursikh and a great kirtani, whose tunes are used by many of today's kirtanis, but what actually happened to him? why was he excommunicated?
Loved their kirtan as a kid as well and still listen to the old recordings.
I don't know the full ins and outs of the controversy surrounding them but you can search yourself online and get an understanding of what the shabad vatara group say about ithaas, Gurbani and Greatest Gursikhs and make up your own mind.
He was excommunicated from Panth for doing Amrit Sanchar without any Maryada. Bhai Ranjit Singh was doing sewa as Jathedar Sri Akal Takht Sahib when he was excommunicated.