Why do even intelligent and educated people often believe nonsense? For example, Arthur Conan Doyle, the writer who invented Sherlock Holmes, the detective who solved his cases with scientific precision.
Therefore, Conan Doyle knew very well what empirical evidence and rationality is, and yet he was a follower of spiritualism. His friend, the famous magician Houdini, tried unsuccessfully to convince Conan Doyle away from this humbug, probably arguing in a similar way as Sherlock Holmes solved his cases: by referring to evidence and rationality.
The reason why Conan Doyle believed in spiritualism: His wife was a well-known spiritualist who also organized séances. So if her husband had been convinced by Houdini, he would have admitted that his wife was a fraud who took advantage of people's credulity.
Conan Doyle, however, apparently loved his wife more than the scientific method, and that is why he remained a follower of spiritualism throughout his life, although by using his intelligence and education he would have been able to debunk this as humbug.
And so it is in many cases: We believe in things because we have a vital interest in these things being true. And reason then serves only to justify this belief.