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.
And while that can be dangerous, I would point out that we should never fall into a position where self-determination and self-protection are something we posit. Those things are automatic before you enter the conversation. So keeping in mind self-worth and survival, I think the major danger of the Light of Day fallacy is the easy avenue it gives you to hand over your darker shit to somebody else, and hate them for it. Classic scapegoating: they're not people, the Newlins say, so it's fine to hate them. Which is incredibly damaging, because "them" is not "you," and actually it's always you. And the reason Jason drags Eddie along everywhere he goes is that he instinctively knows that: whatever reasons he had for fearing or hating Eddie didn't originate with Eddie, and weren't valid.