Not surprisingly, I'm seeing less of this quote this election season. I think the reasons I'm going to outline are troubling other people.
It sounds like a good sentiment. There's a good bond between humans and its importance message to it.
The trouble I always come to, however, is that Thomas Jefferson owned human beings. I think that would be a difference that would cause me to withdraw from any friendship he and I could have, no matter how otherwise troubled he might have been about the institution of slavery.
Now, the standard reply is that it was a different time and people responded differently to those issues at that time, and supposedly the pro-slavery crowd is good and buried. Purely for the sake of the argument, I'll ignore the many slavery apologists one hears about and accept this.
There's an old joke of varying attribution.
The man asks a woman if she would have sex with him for a large amount of money and she agrees that she would. He then offers a very small amount and she says something like "What do you think I am?", to which he replies, "We've established that, now we're just haggling over price."
Here's an article about the attribution of this story for anyone who is interested, Now We’re Just Haggling Over the Price.
That's how I feel about the politics and friendship. Once we've established that there's something out there that a person could believe in that would be disturbing enough that it would make being friends with them untenable, it's no longer a bedrock principle I can live with. The line is definitely out there. Now we're just haggling over price.