I haven't read the whole thread, so I don't know if someone already said this… but my guess is that they were atheists. Either that or some false New Agey type religion that teaches there is no truth, etc... No such thing as a true right and wrong, yada yada. I don't think this is a political thing, as much as it is the way one views the world. (Although of course one's worldview does have an effect on one's politics.)
There's no mention of religions. They were simply
biking. That's it. They did a tour around Iceland first and liked it so much they launched a mega-global ride from southern Africa up its east coast, then off to I think Morocco and Turkey, before Tajikistan. Just literally seeing the world, simple as that.
Anyway I don't think there exists a religion that espouses "there is no truth, etc" whatever that means. But again it isn't a religion story.
I know there wasn't a mention of religion, that is why I said "my guess is…"
As for truth, that's a big topic, and too much to get into on this thread. Yes, they were biking, but that wasn't the point of the story. The point was that they didn't believe in evil (and that rose-colored thinking got them killed.) And
my point was that that sort of thinking – that rejects the concept of evil – usually comes from atheists or people who are into false religions.