And I left when even all of my own groups (one of them with 60000 members) were taken by Indian spammers. Some of the groups would receive hundreds of Indian Job placement, coupon sales, company advertisement and other types of spam.
Orkut's communities were their top offering and it was basically killed by spam (they could have removed all posts by members with high rate of spam reports).
Same as you I do not have anything against Indians, Brazilians or Chinese. But their huge numbers (and by the same ratio, spammers among them) and sometimes their insistence of using their own language could starve any resource if they are directed to it.