I'm glad that you brought up the free speech issue, and how it was subverted by pornographers to get around obscenity laws. Its a nuanced discussion, but a very important nuance. Freedom of Religion, like Freedom of Speech, are enshrined in the Bill of Right. There's nothing in the Constitution about freedom to produce pornography. The way that this group of pornographers got around obscenity laws was through lawfare, and what opened the floodgates was the Miller v California case. That's the "I know it when I see it" definition of obscenity, where material appeals the "prurient interest" and lacks any "serious literary, artistic, political, or scientific value" or SLAPS test. The effects of the Miller ruling was that in order for material to be considered obscene, it has to meet a very difficult 3-tiered test of violating community standards, being patently offensive to the average person, and if the work lacks SLAPS. In setting such a high bar for a work to be considered obscene, Chief Justice Burger essentially created the legal avenue for the widespread production of pornography.
It first started with the Roth case almost 2 decades earlier, but the Miller case is what opened the doors for the widespread distribution of pornography. And that's how the sexual revolution was codified into law, via jurisprudence. It only became a free speech issue after dozens of lawsuits from the 1950s through the 1990s.
