I assume the th couldn't be copied because it's a ligature, which makes the publication look better.
doesn't it also imply that humanity should not accelerate de novo AI-related tech
Correct. This is a key piece of recommended differential technological progress, and this recommendation is stated explicitly in both "AI as a negative and positive factor in global risk" and in "Intelligence Explosion: Evidence and Import."
A couple of minutes of research points to this post about ligature in pdf: Make ligatures in Linux Libertine copyable (and searchable). It appears that there are ways of configuring a TeX document so that ligature can be more reliably copied out of PDF as plain text (this depends on correct support of copying out by PDF readers, but some ways of creating PDFs make more readers handle this operation correctly).
Here is a short new publication from the Singularity Institute, on the 2-day workshop that followed Singularity Summit 2011.
Note the new publication design. We are currently porting our earlier publications to this template, too.