These "rationalists" understand that beliefs should be evaluated on whether they match what we observe, rather than preconceptions about which buckets certain ideas fall into. If the Southern Baptist Convention had announced a theological breakthrough in 2022 that lets them map out the precise calendar dates of the events in Revelations, and using this map they made a series of specific predictions that ended up coming true, it would be rational to start studying End Times Christianity in more detail and irrational to say that it's religious so you're not going to worry too much about it.