The original spoilage came from ... something like ENTERTAINMENT WEEKLY (or some such mag) so DC is just acknowledging the article. Yes, they are the ones that told them in the first place, however.
The reason they do this is the same reason Marvel does it. Jump those sales.
We, as comic readers, have already heard (most chances) of how big (comic book wise) the issue may be, even without truly knowing the exact reason, but there are tons of non-comic buyers that may see
and rush to buy that issue. Thinking, falsely:
A) That it is the original Robin that they know from their youth (through comics, cartoons or the 60's TV show)
B) That it will be a valuable piece of collector stash
C) Both of those
This book will now sell out at most comic shops the same way the "death" of Steve Rogers did a few years back, when Marvel used the same marketing ploy, releasing the spoiler to Newsday (or whatever it was).
Why do they do it when they know it will (can) piss off the readers? They know the readers will buy it anyway. They know they already have those sales in pocket, so what's the harm in adding a few more non-buyers? They don't care about the faithful readers. It's money, money, money.
DC and Marvel's goal is never to make the buyers happy, it is to get the buyers money. You know you can't spell "corporate" without RAPE
