If you believe that laws forbidding gambling, sale of liquor, sale of contraceptives, requiring definite closing hours, enforcing the Sabbath, or any such, are necessary to the welfare of your community, that is your right and I do not ask you to surrender your beliefs or give up your efforts to put over such laws. But remember that such laws are, at most, a preliminary step in doing away with the evils they indict. Moral evils can never be solved by anything as easy as passing laws alone. If you aid in passing such laws without bothering to follow through by digging in to the involved questions of sociology, economics, and psychology which underlie the causes of the evils you are gunning for, you will not only fail to correct the evils you sought to prohibit but will create a dozen new evils as well.

--Robert A. Heinlein, Take Back Your Government

I think that there's probably a lot of exploitation, ranging from human trafficking, to exploiting people who have no other options, to roping people into pseudo-pyramid schemes, to garden variety encouraging potentially harmful conduct stemming from untreated psychological issues (which can apply to both porn actors and porn consumers).

But I also think that for any possible harm that a legal and properly regulated sex industry could do, an illegal and stigmatized sex industry is a thousand times worse. So the key is to recognize that there is an undeniable demand for porn, so we might as well do everything we can to minimize the potential for harm for all possible parties involved.

Also some of those Rule34 artists are just... they're both some of the most amazingly talented artists and some of the most depraved perverts on the goddamn planet, sometimes at the same time. Bless their weird little hearts.