Davey ji
The caste system as an historical fact in India was and to some extent today is much more than a club. Freemasonry, by the way, is an ancient secret society whose members seek to be initiated at increasing levels of secret knowledge and understanding. A simplistic description because I want to move onto the caste system.
The caste system in India is thousands of years old. It has been historically a religious, political, social and economic structure around which the lives of the population were organized and ordered. The origins of the caste system rise with the Law of Manu, who may have been a mythological character, but many consider him to be a fact in history. Manu wrote or issued a code for social organization that included many traditions and practices, including the caste system. These practices that regulated life in India, up to the present. The caste system was outlawed after the liberation, and I believe the year was 1950.
One's caste (or rather varna) was a marker of one's spiritual identity and level of development as well social identity. Individual souls took rebirth to master moral and spiritual lessons in one lifetime, and then to be then reborn into the same caste, again and again, until all the lessons were learned and all the spiritual debts were paid. Caste and reincarnation are indistinguishable in a strict understanding of the Law of Manu. So souls reincarnated through levels continually. Caste kept reincarnation organized so that the lesson of one caste -- humility for untouchables - would be distinguishable from lessons assigned to other castes. And certain religious experiences were forbidden to lower castes because their souls were believed to be unsuited. For example, if an untouchable were caught reciting the vedas he/she would be put to death. Similarly certain economic activities were forbidden to members of various castes. Brahmins could do x or y, but not z. And so forth.
All of the Sikh Gurus were members of the Khashtri varna or caste of warriors and business men. Many of the Gurus' followers were members of the Jaat varna, famers and craftsmen. In fact the word "jaat" in Gurbani has been translated to mean "caste" and to mean "status." And there is a lot of historical information and cultural lore surrounding the contributions of the Jaat varna to the spread of Sikhi.
What does this have to do with Sikhi? Well there are many Sikhs in India who can trace their family lineages back in some cases more than 1000 years, to a time before the Sikh gurus. The historical memory of one's caste dies hard. Why? Because with caste comes one's sense of clan, family and personal identity. People simply do not shed their cultural memories at one stroke of the clock, and then change over night -- because with culture comes a sense of identity and place in the world. Sikhism decries the caste system. Yet people cling when there is no longer any logical reason to continue with political, social, and economic structures that regulated life when conditions were very different. So when Guru Nanak united the Jats and Khashtri's, and when he declared there is no Hindu no Muslim, he made a lot of sense. To the people listening at the time Nanak's message was a message of liberation from injustices and oppression of the past. Unfortunately someone can unlock the door to our prison cells. But we are the ones who must decide to walk through the door and out of the prison.
Please do not be hard on Sikhs because of what you have observed. Many of us have accepted the path to liberation given us by Nanak. Others know better, but have not made the choice. And individuals among the Sikhs are not alone in persisting with obsolete and oppressive traditions. Look around you.