I also have this weird feeling that there was some assumption of gentleman's decorum back then even with those one disagreed with.

I appreciate his "forgive them, educate them, and move on" ideal. As if surely, once they've learned how things are, they will calm down! I wish it were that way.

But I think he'd be (im/de)pressed with just how low the bar has fallen when it comes to civil human behavior, general education esp. in civic affairs, and practical reasoning. There is no line too far anymore. There is no punishment for violating foundational social contracts or civil discourse.

One half is constantly flabbergasted that the other half keeps flagrantly violating the power of their office and saying "So what? I'm winning."

We're just so far past the point of reason now.

Edit: Also remember, Jefferson wrote this long before the Civil War. I believe his point in "forgive them and move on" was optimistically more in the interest of preserving the young Republic at all costs, rather than letting it crumble from the inside with internal feuds. (As is the fate of many rebellions)