According to the article, the stores were running malicious javascript which grabs people's credit card info. This obviously means they are vulnerable in some kind of way, but I fail to see how this is reasonably likely to be exploited. Even if it was, you also have to consider the benefit of warning the users.
I am not a security expert though, and I might be missing out on something.
I am not a security expert though, and I might be missing out on something.