I would agree with you if you were talking simply about Markdown, but it seems you don't understand the point of HAML. Markdown is a complex syntax that loosely translates to half of HTML. It's good for user-input, because it's designed to be written like users already write stylistic formatting when the result will be plain ASCII, but it's not HTML.

HAML is HTML—it's a one-to-one conversion—but it's simpler and more concise to write. It's what HTML should be: no closing brackets, no line noise, and simple syntax to access DOM-relevant attributes (class and id). If I had the option of immediately converting all HTML worldwide into HAML, and all HTML parsers into HAML parsers, I'd sign up in a second.

Also, I don't need to see the raw HTML any more, because that's not the point: it's like looking at machine language instead of assembler. They're equivalent, so why read it the painful way? When debugging a page layout in HTML, I actually find it more useful to convert it into HAML first.