This is probably a very european viewpoint, but I find it amazing how shocked people are by children seeing porn, but don't bat an eyelid when kids are exposed to violence on television or in movies.
The biggest example from my own childhood was WWE (WWF at the time). The simplicity of the scripts etc seemed to be explicitly targeted towards kids who would then, predictably, try to copy the wrestling moves on their friends.
It's a million times more harmful than seeing the human body sans garments.
Obviously there are specific types of porn that I'd be mildly concerned by my child being exposed to, but generally speaking it's the violence and inherently problematic power structures within that are the fundamental issue, not the nudity.
Porn isn't mere nudity, and much of it is extremely violent. It is designed to flood the brain with dopamine. Brains, especially developing brains, which are constantly flooded with dopamine begin to produce less dopamine to offset the flood. Low levels of dopamine cause all kinds of psychological and emotional issues.
Mainstream isn't terribly violent, but it's also not really a good representation of sex that women seem (in my experience and what my lady friends have told me) to typically enjoy. Lots of vids of roided out guys jackhammering until a woman is raw and her mascara is covering her face.
But there isn't really just 'mainstream' anymore. Weird face-slapping or gagging or bukkake stuff is a click away from the front page, frequently in 'suggested videos'.
The biggest example from my own childhood was WWE (WWF at the time). The simplicity of the scripts etc seemed to be explicitly targeted towards kids who would then, predictably, try to copy the wrestling moves on their friends.
It's a million times more harmful than seeing the human body sans garments.
Obviously there are specific types of porn that I'd be mildly concerned by my child being exposed to, but generally speaking it's the violence and inherently problematic power structures within that are the fundamental issue, not the nudity.