1. Yes they did, I did the Moral Absolutes ping list for about a decade, and I remember that case.
2. Obsenity, pornography and blasphemy such as is tolerated (or celebrated) today would never have been countenanced by them, and the mores of that time (much better than ours today) did no countenance such things even by their more stringent parameters.
3. The hack comparative religious theory is considered by practicing Hindus to be blasphemy and obscenity. Why shouldn’t they forbid it if they want to?
(2) You are again wrong about the Founders. The works of Thomas Paine were inarguably blasphemous by every 18th century standard. And Titus Andronicus was inarguably obscene - yet was printed at Philadelphia in 1795 even as it was being bowdlerized in its home country.
(3) They shouldn't ban it, because they should value liberty over despotism. They should recognize that all human beings have inalienable rights.
There is also the practical difficulty of allowing governments to devide what can or cannot be said and what does or does not constitute something as amorphous as "blasphemy" and "obscenity."
(4) Why do you strain so hard against the facts to defend the Founders (from something they were right about) when you clearly deplore the Declaration they risked their lives for?