Society has drawn a line: porn is legal. Sorry you don't like it. Feel free not to participate.
Not everything legal is healthy for society. Abortion is legal. Homosexuality is legal. The line has to be drawn somewhere. It may not end in making things illegal but there has to be standards set in society.
Laws can be changed in a "free" society. Sorry you don't like it.
Some people want to shift the lines in the sand such that everything they disagree with is banned. They want to live in something similar to a Muslim state, one where their religious laws are made state law. They want anyone who violates their particular version of morality to be arrested. Of course to them their version of morality is not a "version" at all, it is the is the only way, the right way, and anyone who deviates from it must be punished. There have always been people like this, and there always will be. They come from all religions and different denominations. They may not agree on all the particulars, but they are all the same.