Hi Andries,My teenage years were full of the Gita and the 'Gospel of Ramakrishna' but there are many more reasons than being conned by a spurious guru to decide that the Vedanta doctrine is false.
The main reason as far as I am concerned is that nobody ever gets enlightened, at least nobody alive now and nearly all the people who claim they are enlightened are shonky gurus and most of the rest are seriously demented and the others are just nice.
How about making a more mature decision about whether something is worth believing and not just because you've been betrayed.