Your unsupported belief that the founders would protect pornography is ludicrous.
Pornography is demonstrably more dangerous than shouting fire in a crowded theater.
Can you show me in the Constitution where it says “Free expression, except pornography?”
It’s not up to you to ban things outside your home that you don’t like.
The founders did not establish government to enforce any one religious morality. There is no enumerated power listed in the Constitution giving them that ability. Therefore its not in their wheelhouse.
Now, also, they lived in a time where almost everyone in America was some form of Christianity, and the states themselves had state endorsed denominations, and the state governors would give religious proclamations on certain occasions, but they depended on the religious powers that were, to give the citizens moral foundations and encourage morality they thought was proper.
Its not govt’s role to push religious morality. Govt needs to get out of the way of religions to do that. Go t isn’t equipped to do it.