Yeah but no but
While I see where you're coming from, and don't much fancy the idea of my "beautiful" sites being butchered in this way either, 2 things:
(a) As a web author/provider, you serve up and transmit a page of HTML and some other odds and sods in a presentational style and structure of your liking. Once it's left your server and is represented on the client's screen, it's really up to them what they do with it. By way of an analogy, suppose I buy a newspaper, throw away the sports pullout, and rip the top two inches of celebutard-baiting Heat-magazine-style "teaser" bollocks off the front page before I start reading. Does this make me a thief? No - I bought the paper, it's my right to make it into a funny hat, without reading any of it, if I so choose.
(b) Readability is something the user has to voluntarily use after loading the original page; it's not like the user never even sees your proffered layout and content (although if they were really hard-assed I suppose they could combine it with Greasemonkey) - I don't know what the score is with Safari but I bet it's not automatic either. So your analogy doesn't quite ring true - it's more like you'd be standing outside the store telling everyone who walks out clutching a brochure (and can be bothered to listen) that pages 1-4, 6-7 etc. are drivel, and *they* ought to rip them out and oh, I've some scissors if you need 'em. To be fair, the fruit police would probably give you a doing-over for that too, but for once I don't think they could do much legally, except maybe harrassment charges or an ASBO.
Here's a thought: maybe if the authors of informational sites worked harder to strike a reasonable balance between content and window-dressing/ads/etc, then widgets like these would never have been conceived of in the first place.