It's a peculiarity of AdSense that turns what would normally be helpful behavior (please check out my advertisers -- they have really good stuff I personally recommend) into "fraudulent" behavior. The reason is, of course, that the site author has zero input or control over the contents of the AdSense boxes, and as such can't really recommend what's in there. You can _hope_ that what's in the box is a relevant ad for your readers, but you really don't have any way of knowing.

Google could provide a kind of back-and-forth here, to restore the ability of a site author to provide a testimonial for a particular advertiser. An author would have to provide a (short and limited) list of sites and testimonial copy for each one.

A sailing site could then, for a particular sailcloth manufacturer's ad, provide a short testimonial noting the high quality of the product, etc...and Google could serve up that custom testimonial along with the ad.

You'd either have happy advertisers, or not.