Sarah chases him out on the porch, desperate to keep him close, and asks him to just talk to her, work it out, give her something to work out. He swears there's nothing to talk about, so she starts with the obvious: "The first time I laid eyes on you, I knew there was something special about this one. I knew the Lord had sent you to me, but it wasn't till today that I knew why." You can see everything, every single thing he thinks or feels or has ever thought or felt, on his face. This is the easy part: "Because we're so much alike. We want to see the best in others so badly that sometimes we overlook the worst."
"That kind of does sound like me," he agrees, which is half true. If you look at it in that hateful, small way, then yes: he's naïve. But that's just the Light of Day fallacy: to love the light, you must hate the darkness. Which is just a way of opting out of being present for anything, just like any dogma. It's lazy, and it harms you in the long run. Here's an analogy: If a gay guy sleeps with a woman, he's still gay, right? No question. But if a straight guy sleeps with a man, he's gay. Automatically, no exceptions. It's tilted that way: Open the gate, and all the evidence comes sliding down into the gay part of the box. It's a fall from imaginary grace, and you can't get back. (This is also the reason I love Jessica the most, after Jason: she's the only one that's lived both absolutes. Total asceticism, total abandon. She's the only person who can consciously make the choice, and has the horrific, hard-won training to be sensible about it. She was homeschooled in just this balance.)
In the same way, Amy was awesome in some ways, deeply not-awesome in other ways. Maryann too. The Light of Day fallacy says, then, that nothing Amy or Maryann ever says or does is of merit: you put a big old X over their face and move on. That's lazy and stupid, and people aren't like that, because nobody is able to keep everything on the top of the mountain all the time. I daresay even the Newlins have something to teach us, too, although we haven't seen it yet.
So when Jason said you love the whole person or else it's not love, he was talking about this thing. And only Jason -- and Sookie, later in this episode, with Bill -- seems concerned about that, about taking charge of your own reactions in that way. Which is why he's my favorite, because nothing freaks me out as fast as watching somebody let half the world wither away like that, and at least he's struggling with it. It's the same reason V made him want to fuck in the dirt: the loss of categories. Crossing state lines, into other territories. He doesn't have the words, and Sookie only has them with Bill because of her disorder, but that's what they're dealing with: loving the person and not the acts.