How do you know most CP is done by family members with willing kids? Is there any proof of that? There is no way for you to know for certain (unless you were there) that the CP you're viewing was made willingly or not.
The only reason so many people believe CP is full of actual child rape, or otherwise lack of consensual participation by the young people involved in it, is due to claims and implied statements from the small handful of LEOs who are legally permitted to view it, and they have a vested interest in having the public believe the worst. Is there any proof that they are telling the truth? Isn't it curious that they have refused to allow any investigative journalists to view the CP in their archives to determine the veracity of these claims? And is it justified to always assume the worst without a bit of evidence?
And yes, there is evidence that the cops lie profoundly about what the majority of CP consists of, and you should probably read my detailed analysis of the subject on this essay ⚠️ ↗ I wrote for NewgonWiki.