Re: Virgin Mary - In a Chicago Underpass
people see it as a "sign" that what they believe in is true, it gives them hope and gives them conviction to increase their faith.
We live in strange old world where we as humans have been the safest and healthiest we have ever been but still very empty emotionally.
when you can mentally translate a splodge on a wall into a divine figure and "feel" the love and warmth it provides you, why not!
(am a sceptic myself)