TL;DR - From the books perspective it seems that all those brought back by The Lord of Light are "undead". The shows perspective is not as clear.
The quote you have provided was part of a larger Time interview. Here it is in context:
Q: Did Lady Stoneheart come about because it was hard to say a permanent goodbye to Catelyn?
A: Yeah, maybe. That may have been part of it. Part of it was also, it’s the dialogue that I was talking about. And here I’ve got to get back to Tolkien again. And I’m going to seem like I’m criticizing him, which I guess I am. It’s always bothered me that Gandalf comes back from the dead. The Red Wedding for me in Lord of the Rings is the mines of Moria, and when Gandalf falls — it’s a devastating moment! I didn’t see it coming at 13 years old, it just totally took me by surprise. Gandalf can’t die! He’s the guy that knows all of the things that are happening! He’s one of the main heroes here! Oh god, what are they going to do without Gandalf? Now it’s just the hobbits?! And Boromir, and Aragorn? Well, maybe Aragorn will do, but it’s just a huge moment. A huge emotional investment.
And then in the next book, he shows up again, and it was six months between the American publications of those books, which seemed like a million years to me. So all that time I thought Gandalf was dead, and now he’s back and now he’s Gandalf the White. And, ehh, he’s more or less the same as always, except he’s more powerful. It always felt a little bit like a cheat to me. And as I got older and considered it more, it also seemed to me that death doesn’t make you more powerful. That’s, in some ways, me talking to Tolkien in the dialogue, saying, “Yeah, if someone comes back from being dead, especially if they suffer a violent, traumatic death, they’re not going to come back as nice as ever." That’s what I was trying to do, and am still trying to do, with the Lady Stoneheart character.
Q: And Jon Snow, too, is drained by the experience of coming back from the dead on the show.
Right. And poor Beric Dondarrion, who was set up as the foreshadowing of all this, every time he’s a little less Beric. His memories are fading, he’s got all these scars, he’s becoming more and more physically hideous, because he’s not a living human being anymore. His heart isn’t beating, his blood isn’t flowing in his veins, he’s a wight, but a wight animated by fire instead of by ice, now we’re getting back to the whole fire and ice thing.
So we see the lead-in is Lady Stoneheart (the prior question was about how the Red Wedding was hardest scene for George to write). That gives us the link that Berric, Caetlyn, and Jon have all been resurrected, and all in the same way.
I tend to look at these answers from George pertain more to his books than the show. He even alludes to that in the same interview:
I’ve sat out seasons 6 and 7 too, just trying to concentrate on this book, which as you know is massively late. So in that sense, my involvement in the show has diminished over time, though, I’m still here whenever they want to talk to me, and I’m always glad to weigh in.
I think one of the biggest ones would probably be when they made the decision not to bring Catelyn Stark back as Lady Stoneheart. That was probably the first major diversion of the show from the books and, you know, I argued against that, and David and Dan made that decision.
We know Jon has not been brought yet back in the books, this seems to major a plot point to change. However, Jon does seem "alive" (we see take some big gasps of air when is first revived) in the show and since Lady Stoneheart was cut from the show. Dan and Dave may not follow the whole "fire wight" path.