well, we can only resort to public shaming at this point... share across all social media... LOLYou suck WD and I hope you get to waste time and money on a class action. Although it will only likely be a pittance of compensation for users it will hopefully make you disclose this type of customer last change in the future.
It is unfortunate that the law is unable to keep up with this kind of tech trickery. States have weight and measures laws so you cannot market a pound or whatever of something and then give the customer less than promised. What WD did is exactly akin to that, they promised fitness and performance for a particular use and then later secretly made a change to customers' detriment.