Did YOU actually read the letter? The whole letter and not just the excerpt that you linked to? Here's the whole letter.
Maybe you should do a little more digging before you grab your pitchfork.
First, even in the excerpt you cited, Jefferson acknowledges that progress can be made towards forming a general set of rules. He's not saying there shouldn't be anything such as IP (which is what you and every other knee jerk engineer seems to quote this for).
Second, he actually requests that the very letter you're excerpting not be used to misrepresent what he's saying:
"I have thus, Sir, at your request, given you the facts and ideas which occur to me on this subject. I have done it without reserve, although I have not the pleasure of knowing you personally. In thus frankly committing myself to you, I trust you will feel it as a point of honor and candor, to make no use of my letter which might bring disquietude on myself."
Long story short, you do much disservice to your point when chastising me for cherry picking points but then rely on them yourself as your sole support for your main argument.
And I'M the troll.