I've been spending quite a bit of time interacting with the young-earth creationist community on Reddit and YouTube. It is closely related to flat-earth, though there is one significant difference: YEC is overtly religious, and specifically Christian. Other than that many of the forms of argument are the same. From that experience I have made two observations: 1. These people are not idiots (at least the YECs aren't,…
Why would some point of existence or meaning lead specifically to Christianity?
So the first question is, "Is there something besides the physical world -- besides atoms and energy and time?" If you say "yes", then you've ruled out materialism (which some people confuse with science).
There are a number of things in our human experience which (in my opinion) are inconsistent with a materialistic worldview. The sense of meaning and purpose is one. Morality is another. (Not trying to argue this here, just trying to answer the question.)
Then you can say, OK, but that could be Buddhism or Shintoism or Islam or anything. So the next set of questions might filter out reincarnation-style religions and get you down to the Abrahamic religions (Judaism, Christianity, Islam); and then you might look specifically at evidence about Jesus' resurrection.
Not all Christians are Young Earthers; and Young Earthers are certainly not Flat Earthers. But there is this similarity: Christianity gives people something that atheism and materialism do not. And so when modern atheists say, "Belief in evolution is incompatible with belief in God -- you have to choose one or the other", then a lot of people will say, "Well if I have to choose, I'm going with God."