I don't see the issue.
If I was getting pounced on by a hundred or so people every time I screwed up, I'd be handing out blocks like flyers at a university campus.
Yeah, if I was getting dog piled on Twitter I'd be blocking like there's no tomorrow.
It's not as if he's hiding something or being a dick about the situation. He made a mistake and is rectifying it, another 100 people calling him out doesn't really change or add to the conversation.
A senior member of IGN making the mistake with the review isn't a good look. But I'm fine with him blocking folks on Twitter.