It is unfortunate that, in many people's understanding, someone who is religious has to follow a particular religious tradition and be labelled as such, e.g. a Christian. It is even more unfortunate that, especially in the West, it is a common misunderstanding that if you are not religious your only option is to embrace reductionist materialism, atheism, and scientism (the belief that science can explain everything) as a metaphysical explanation to the nature of reality. It is a false dilemma. Sadly, this adherence to science as the ultimate truth has deprived us of meaning in our life.
So, why many indigenous cultures use natural psychedelics in their rituals? Because psychedelics, through the ego deflation, help you to have a mystical experience, to connect with the Other Self, the Cosmic Consciousness, the eternal spirit, call it what you like. And, to come full circle to the OP, much of psychedelic Goa trance has this special mystical feeling as well, that you can come closer to the ultimate reality.
It is sad that many party-goers do not share these ideas; for them, dancing and doing psychedelics (and other drugs) is just recreational, purely hedonistic. And they keep living their consumerist, materialist lives, dead in spirit inside them. Not to mention organisers, DJs & artists who just do business as usual, even if they have to turn a blind eye on massive human rights violations; making some extra money and gaining more fame is what matters most .