The fictional book hit on religious views and racial beliefs that defined the South when the book was published. Twain writes with the individual characters speaking in their own Southern language and not just through Huck. This makes the ridicule more effective.
“Huck’s early rejection of Heaven, his later decision to accept damnation- are further instances of Twain’s dialectical counterpoising of the frivolous and the profound” Huck gives numerous examples of why he finds prayer useless such as “why don’t Deacon Winn get back the money he lost”. Pinsker) Basically saying if prayer is going to work shouldn’t it work for a highly regarded person of the church? Of course, the examples are for material things and not of spiritual origin so maybe the reader will forgive the young boy for foolish thoughts.