Admittedly, I don't send personal emails, but on HN or Reddit, I'll often ask experts or people who are at least knee-deep in a topic themselves (or find previous instances where expert(s) was asked).

It's not about laziness, it's just that as somebody who doesn't know anything about established papers or books of a certain field or how it's structured, it can help a great deal to get started if somebody can point in a general direction of where to spend my attention (which is a limited resource). As somebody with dozens of interests across a bunch of disciplines, drawing on existing knowledge has been such an immense time saver and help that I'm always grateful for. There are a lot of books and papers out there. And not all of them are particularly good. If other people have experienced them and share that experience, why shouldn't I want to draw on that?

Also, I've gotten a response as often as I haven't. And when I don't, it really isn't a big deal. You don't need to respond to every request.