It creates a space for people to explore and normalise their distressing sexual interests without questioning the root causes.
Producers will often intentionally seek out vulnerable young women and groom them with promises of fame and riches, only for them to become reliant on painkillers and other drugs to cope with the reality of it.
It creates a market for the abuse of trafficking victims. Most sites don't require verification of consent and most users don't care.
It teaches men to objectify their partners and to see them as something to be shared. There is a huge market now for non consensual revenge pornography. Reddit has seen multiple subreddiys dedicated to non-consensual intimate media.
It provides a safe space for people to express racist, misogynistic and otherwise antisocial viewpoints.
PornHub in its front page today has videos of stimulated assaults and incest. For young viewers it gives them the idea that it's normal to be sexually interested in these things.
I'm not religious. I'm sex positive and believe in being open with children about the realities of life. Pornography stole years of my life, warped my views of relationships and prevented me from reflecting seriously on my own traumas.