From the article:
>This name change has been a long time in the making. As we explained when we announced the rebrand a few weeks ago, we’ve had major issues with a certain gigantic games company which has blocked us from being able to trademark Riot or even Riot.im - a huge issue when it comes to defending users against abusive forks of the app.
I'm willing to bet that was also a factor in their name change. In fact, a quick Google search for Riot brings up Riot games as the first result and the wikipedia entry for them appears on the side bar. So I'm guessing this was the case for the vast majority of Americans.