The Death Note fandom has always resisted official attempts to find canon colours for Matt. Fans had already established their own.
As the only popular character to have spent years only in black and white, it quickly became the norm to depict Matt as having red hair and green eyes. His stripy top was either white or red, with black lines.
But it had never been officially sanctioned.
By the time Tsugumi Ohba and Takeshi Obata made it canon for Matt to have black hair and brown eyes - in How to Read - it felt downright jarring to the fandom. Like some kind of continuity error.
Fans en masse ignored the directive.
It didn't help that the canon itself couldn't seem to settle upon Matt's official colouring. The anime rendered his hair a weird green-black sludge colour. A game recoloured his hair blue. The fans stuck with red.
With the recent advent of the whole Death Note manga being coloured by Obata, suddenly we're back to black hair and brown eyes. This is confirmation by the creators of Matt's absolutely canon colours. So how did the fans react?
But the funniest response so far has to have been a short story, penned by Death Note fan-fiction writer ShinigamiMailJeevas. If you've not yet read it, then I thoroughly recommend Changeling.
It looks like the Death Note Matt fandom is most certainly resisting this canon colouring attempt too. You'd think that the mangaka would just give up and go with the consensus!