I've mentioned it before, but there are a lot of other bands that do the exact same thing. It's not just U2 or this band or that. Even then, it makes sense that someone will hype up a new release for the simple reason that they're excited about it. It's new-ish songs they've written and likely ones they feel strongly about because of it.
Then as time goes along, you listen back and think about how maybe this decision could have been different or how that one guitar doesn't sound right now, etc. One thing to keep in mind is that musicians are not going to hear songs the exact same way we do. Heck, when I write songs myself, I don't hear them from the point of view of a random listener. I think of it as something I'm molding and constantly make decisions as to whether the parts are all correct or not. There are probably artists out there who don't mind just creating something, complete work on it fairly quickly and then throwing it out there. But Edge or whoever gets blamed certainly isn't the only guy that takes their time with things, or says that this could've been better or not.
George Martin once had a quote that sort of summed this up nicely re: a conversation with John Lennon:
It’s a funny thing, John said this to me originally when we were spending an evening together and it shook me to the core when we were talking about old things and he said, ‘I’d love to do everything again.’ To me that was just a horror. And I said, “John, you can’t really mean it. Even Strawberry Fields? And he said, “Especially Strawberry Fields!” I thought, oh s**t, all the effort that went into that. We worked very hard on that trying to capture something that was nebulous.
So it's not being a bad person or wanting to sell a new album... from what it seems, it's just being an actual human being.