This is a wild take. Unless I am mistaken No mercy glorified rape and incest. The core gameplay was to "discipline" your female relative and actively force her into sexual interactions. It was a rape/incest simulator. WhatIWouldn'tDo is dark horror literature at best and it warns readers of the extreme dark themes that occur. Can this be fetishized? Of course, a lot of things are and will be fetishized by some readers, but you cannot compare the two because this creator isn't exploiting sex and basically glorifying rape for the hell of it like No Mercy did.
This might be torture porn for some, or a way for some SA victims to cope, I won't deny that, but at least this creator isn't trying to make a profit for it like the incestual rape fantasy No Mercy was trying to sell.