Jackie: I'm in my dressing gown.
The Doctor: Yes, you are.
Jackie: There's a strange man in my bedroom.
The Doctor: Yes, there is.
Jackie: Well, anything could happen.
The Doctor: Ah...no.
The Doctor: I'm the Doctor, by the way. What's your name?
Rose: Rose.
The Doctor: Nice to meet you, Rose. Run for your life!
The Doctor: Think of it. Plastic, all over the world. Every artificial thing waiting to come alive. The shop-window dummies, the phones, the wires, the cables...
Rose: The breast implants.
Rose: Really though, Doctor, tell me, who are you?
The Doctor: Do you know, like we were saying, about the Earth revolving? It's like when you were a kid, the first time they tell you that the world's turning and you just can't quite believe it because it looks like it's standing still. I can feel it. The turn of the Earth. The ground beneath our feet is spinning at a thousand miles an hour, the entire planet is hurtling around the sun at sixty-seven thousand miles an hour, and I can feel it. We're falling through space, you and me, clinging to the skin of this tiny little world, and if we let go... That's who I am. Now forget me, Rose Tyler. Go home.
The Doctor: [Perusing a British tabloid in Rose's flat.] Oh, that'll never work. He's gay and she's an alien.
Chosen answer: 1) When Stephen Moffat took over he ignored a lot of what had been developed before (there is not in-universe answer). 2) It would have killed Rose, so the Doctor absorbed the energy. His body regenerated before the energy could do a significant amount of damage that would prevent regeneration.