In the U.S., the preferred spelling of the color that’s a mix of black and white is gray. But the writers at Yahoo! Style don’t care about that. They also don’t care that when referring to the footwear, Converse is a registered trademark:
A better question might be: Should writers working for the same Web site spell words in the same way? That’s just one question raised by this teaser on Yahoo! Shine:
Other questions might be: Why can’t the editor spell au naturel? And why can’t the editor proofread?
As to the question about which spelling to use (gray or grey), it probably wouldn’t be an issue if everyone at Shine picked one spelling and went with it.
Although the article teaser uses grey, the actual article uses the more common spelling:
Shouldn’t Shine have some standards for spelling?