Milovana.com

My main problem is how badly they portray BDSM, in the book Grey is an abusive stalker, who plays fast and loose with the idea of consent.

That's not true! I mean, of course it is in the beginning, but it's also stressed that Grey is a man with hudge psychological trauma and very much deviant because of that. During the story he changes considerably. This book is exactly showing the difference between his initial understanding of lifestyle, and between what true BDSM is, i.e. what they end up having.
It depicts the kink exactly how it is supposed to be - safe, loving and consentual.