I remember that article. While they explicitly did call out Club Penguin (in your typical click bait fashion), they admitted in the article that the potential for semi-anonymous communication applied to every online video game and forum on the internet. Club Penguin was also not the only platform targeted with these insinuations - the PS4 was also directly accused of being such a communication method.

Of course, terrorists were also confirmed to be using mail, telephones, text messages, email, and face to face conversations...

Let's be honest, it was a click bait article with no real substance to it.