I don't get this, maybe it is because I now just skim through what TS says and don't fully read it. So I apologies if I haven't fully understood what is going on here.
I've only been skimming, too, but the jist I get is:
1. TS creates a sock puppet on Wikipedia.
2. TS makes the sock look like a CT debunker.
3. TS posts false data to an unrelated (and apparently obscure) page using the sock.
4. After a week, with the data he posted unaltered, he exposes the scam and claims it proves bias on WP.
I'm not sure it proves much, since the page he edited, from what I have read here (I haven't checked it myself), was obscure and rarely visited.
I'm sure there is a level of bias in that people aren't going to trust data coming from a CTist and are more likely to double-check the facts and remove any BS. Wikipedia has a policy against original research and I'm sure most of the CT crap will fall under this umbrella, although there is a need to represent both sides of the argument (not neccessary giving equal weight to each).
I don't think there is a bias in the way of people knowingly not removing bunk data if it comes from a skeptic or main-stream source. The false data he added was removed as soon as it was discovered to be false.
To be fair to TS, I don't think he was trying to have a laugh at the expense of victims - he was just trying to prove a somewhat misguided a point in a very misguided fashion.