First of all please be aware this post contains some abusive language but I hope it will not bother anyone. I apologize for the bad language but that's what the name is.

As I've been doing documentation on existing programming languages attempting to make a complete list of them I stumbled across terrible programming languages, which were clearly not made for actual use and implementation due to their insane difficulty. Languages such as Brainfu*k and LOLCODE or Whitespace are fool languages because they have no real use.

For example, a "Hello world" program written in BrainFu*k. Taken from Wikipedia:

The following program prints "Hello World!" and a newline to the screen:

+++++ +++++             initialize counter (cell #0) to 10
[                       use loop to set the next four cells to 70/100/30/10
    > +++++ ++              add  7 to cell #1
    > +++++ +++++           add 10 to cell #2 
    > +++                   add  3 to cell #3
    > +                     add  1 to cell #4
    <<<< -                  decrement counter (cell #0)
]                   
> ++ .                  print 'H'
> + .                   print 'e'
+++++ ++ .              print 'l'
.                       print 'l'
+++ .                   print 'o'
> ++ .                  print ' '
<< +++++ +++++ +++++ .  print 'W'
> .                     print 'o'
+++ .                   print 'r'
----- - .               print 'l'
----- --- .             print 'd'
> + .                   print '!'
> .                     print '\n'

or another example taken from LOLCODE language:

 HAI
 CAN HAS STDIO?
 PLZ OPEN FILE "LOLCATS.TXT"?
     AWSUM THX
         VISIBLE FILE
     O NOES
         INVISIBLE "ERROR!"
 KTHXBYE

These languages are very difficult to learn/read/work with. My question is - Why do they exist? What is the purpose of them? Also, is there an official "name" for these type of languages?