That is probably because Dane's backstory entails HUGE spoilers. Whereas Grayson's backstory is not quite as relevant to the overall plot so people feel more comfortable discussing it. I mean, it matters contextually, but his past does not shape or influence later events. I can tell you Dane's backstory though if you're really curious.
Danes back story please!
SPOILER WARNING
So, basically Dane was the product of rape. His mother was raped during her heat cycle by a bunch of alphas. In court, it was concluded that what happened to her wasn't rape because she was in heat. Her religious parents disowned her, so she had to take care of Dane on her own and in poverty. She became a violent alcoholic who taught Dane that love was painful and abusive. Part of her loved him, but a huge part of her hated him and resented him because of the circumstances of his birth and the consequences of his existence. She would tell him she loved him in tears only to later beat him and blame him for her misfortunes. She also raised him with the mentality that being an omega is bad and shameful; that is why he doesn't like people knowing he's an omega. One day, she nearly choked him to death. When Dane regained consciousness, he found out that his mother did not kill him, but killed herself instead. It's because of this that Dane does not believe in love and why he does not dare to open up to anyone ever again. Both him and Grayson are severely broken people thanks to shitty parents.
As much I love Grayson why do people only focused on Grayson, I have been curious to Dane's backstory and it's hard to find one. Knowing that every comment only talks about Grayson's childhood