Scattering the spans more wouldn't do much... it's still pretty straightforward to gather the list of css classes used in the page and just piece together the innerText of their elements until you see a dictionary word (or even easier, a space).
In any case, there's always the impossible-to-defend-against attack: just hit PrintScreen on the keyboard, paste to MS-Paint and run the image through one of the many OCR websites that you can find via Google. Maybe even run it through MS-Word's autocorrect after that.
"Tired of people stealing your content? Looking to make copying HTML text a huge pain for your users? Sick and tired of useful, well-made Python scripts?"
I can imply your message, but without saying it, it's not a message! You just offered a tool that some ass-hats can use to obfuscate their blog. However I don't fear this, because people know to avoid shit and avoided DRM too. Not because people care about privacy (see Facebook), but because people hate getting limited in their abilities on a free and living medium
javascript:d=document.createElement("div");d.innerHTML="<style>span:nth-child(odd) {display:none;}</style>";document.body.appendChild(d);