It seems to me that most points made here are caused by A) a lack of understanding of the benefits of such tools, and B) an unwillingness to adapt existing code

It seems to me that most points made here are caused by A) a lack of understanding of the benefits of such tools, and B) an unwillingness to adapt existing code to the new toolkits. It seems an unfair criticism of a pre processor if you're unwilling to adapt to their usage. For me, the ability to have mixins, sprite generation, smart media paths (eg image-url, font-url, etc, in SASS), automatic concatenation, CSS3 tools and much more is worth a small learning curve. If its really painting you, try SCSS an just prefix existing files with that extension. Most if not all your styles should work out of the box.