Instead of putting thoughts (as if anyone could really knows what goes on in there) in Alan Moore's head and words in his mouth, I rather let him tell it:
Alan Moore, writer of Supreme and Tom Strong, on DC's 1986 Superman re-boot:
"Superman himself seems to have been a bit lost for a number of years, it's not the character I remember. What made the character appealing to me has been stripped away in a tide of revisionism. Given that I was somebody who sort of helped bring in the trend of revisionism in comics, I've got to take some of the blame for that. But it seems to me that there might have been a case of the baby being thrown out with the bathwater with the original Superman."
"What it was with Superman was the incredible range of imagination on display with that original character. A lot of those concepts that were attached to Superman were wonderful. The idea of the Bottled City of Kandor, Krypto the Superdog, Bizarro, all of it. These are fantastic ideas, and it was that which kept me going back each month to Superman when I was ten. I wanted to find out more about this incredible world with all of these fascinating details."
http://superman.nu/a/moore.phpFrom a great interview nearly all about Watchmen from TwoMorrows:
CBA: You're writing super-hero comics again.
Alan: My super-hero comics are very different, I think. After I finished doing Watchmen, I said that I had gotten a bit tired of super-heroes, and I didn't have the same nostalgic interest in them, and that's still very true to a certain degree. Even if I was actually writing for DC Comics again (and I often read Superman), I haven't got any interest in Superman now. I'd gotten interested in the character when I wrote it, but it wouldn't work for me now—the characters are different, the whole world is different. [laughs]
CBA: But you were able to purge yourself pretty quick, right? You didn't write that many, maybe four or five Superman stories?
Alan: And that was enough. Those were ones I wanted to write, but since then, most characters have changed so much that they no longer feel to me like the characters I knew. So, I wouldn't have that kind of nostalgic interest in those sort of characters anymore. At the time, I was also saying I didn't feel that if there was some strong political message I wanted to get over, probably super-hero comics were not the best place to do it. If I wanted to do stuff about the environment, that there didn't need to be a swamp monster there, for instance. When I did Brought to Light, about the CIA activities in World War II, that story would not have been greatly enhanced by a guy with his underwear outside his trousers, you know. And also, there did seem to be a rash of quite heavy, frankly depressing and overtly pretentious super-hero comics that came out in the wake of Watchmen, and I felt to some degree responsible for bringing in a fairly morbid Dark Age. Perhaps I over-burdened the super-hero, made it carry a lot more meaning than the form was ever designed for. So, for a while, I went off to do stuff that was very non-super-hero, and going into other areas I was interested in.
The super-heroes I'm doing now are not carrying strong political messages, and that's intentional. They're entertainment, and I think there are very few genres actually as entertaining as the super-hero genre. And entertainment can be emotionally affecting and intelligent, but I don't really want to lecture in the same away I did when I was younger. I'm not trying to break or transcend the boundaries of mainstream comics, because mainstream comics is in pieces, you know?
CBA: Well, you're about the only one left standing, I would think. [laughs]
Alan: There's no point in trying to transcend the boundaries of something that's already shattered, you know? [laughter] The thing to try and do is to surely try and come up with a strong form of mainstream comics, with some occasionally transcendent elements, but not, "Let's smash the envelope!" Perhaps I have more of a constructive approach than deconstructive.
full interview here:
http://twomorrows.com/comicbookartist/articles/09moore.html