I don't buy that. For example Ramana Maharshi was awakened and he self-realized suddenly without following any path. There were awakened people before Buddha, and there are awakened people today without having followed any path.

The idea that only Buddhism holds the keys to self-realization is dangerous, frankly. The Catholic Church want you to believe the same thing, that only the Papal hierarchy can direct you to God.

"self-realisation" has nothing to do with enlightenment in a Buddhist sense. I understand it is tempting to subsume all religious experiences into one super-experience, but they really are qualitatively different: in Buddhism it is about permanently ending suffering and the cycle of rebirth, in Advaita Vedanta (e.g. like Ramana Maharshi) it's about, as you say, self-realisation or perhaps "realising you are a part of God". What makes you so sure that these two things are necessarily related? I see this quite a lot, people want to think that Buddhist enlightenment is qualitatively the same thing as others, and that all the different spiritualities point to the same ultimate goal, which is some kind of spiritual union with God. Well that's _not_ the goal of Buddhism. Do you have any actual evidence to suggest it is?

> What makes you so sure that these two things are necessarily related?

In short, I take these people's word for it because I see no reason to doubt it, just like any non-enlightened person takes the word of Buddha or Buddhist monks that they were/are enlightened. There are numerous instances of Hindus like Ramana and Nisargadatta claiming that their state of mind is identical to what Buddhists call Enlightenment.

If anything, it's Buddhism that has these crazy religious narratives about the cycle or rebirth and so on. Nisargadatta, for example, rejects all this stuff. God, reincarnation, is all conceptual fluff; ignorance. Because what is the "reincarnation" concept to the silent mind? It a disturbance.