They want the multiverse to be as crappy as they can possibly make it as to reinforce their point that a multiverse is too confusing and a single Earth is preferable. THEY'RE ERECTING A STRAW MAN ARGUMENT. Let's argue that a multiverse is too confusing by making an incredibly lame confusing and convoluted multiverse! Let's make it convoluted by putting multiple versions of The Crime Syndicate who themselves are supposed to be ONE variation of the JLA. Let's have 2 Captain Marvel's with hardly any difference between them. Let's have another JSA! Let's have not just a few Earth's at a time to be introduced to gradually, but lets have TONS of them all at once and have them numbered and introduced randomly!! One day you'll be on Earth 3, the next day you'll be on Earth 41 with no rhyme or reason. Earth X will suddenly have some random number attached to it that's hard to remember!
whomod makes an interesting point. Furthermore, this sort of thing is not without precedence at DC.
Not only was there the incident with the G(olden) A(ge) Superman in Infinite Crisis, but there was the whole Az-Bat plot. Denny O'Neill has said many times he created Az-Bat to silence fans who wanted a darker, more Marvelized, Batman, giving them what they ostensibily wanted, but doing so in a way that would make them dislike the character and hope for the original's return.