In an update on the Sony Playstation Blog, Naughty Dog co-president Evan Wells wrote that the decision to pull the plug on the feature was driven by "some concern about the frequency of updates."
Some reviewers have had early access to the game and selected the option to update their Twitter accounts as they completed each chapter of the game. This has resulted in some Twitter feeds being updated multiple times an hour. We obviously want to provide the best experience for everybody, so for the time being we've disabled Twitter updates on chapter completions.
An update down the line will also remove the option from the menu.
Earlier today I turned the option for the auto-updates on my Twitter account for chapter completion. While a few other bloggers complained about the auto updates, quite a few of the responses in my Twitter feed was about the speed in which I was completing chapters, not the regularity of updates.