Because he asked what he could do to improve the reception of his comments, and was told that a major problem was that he spread random ideas across dozens of comments, cluttering threads up, and then proceeded to follow that advice. (Or, in more Less-Wrongian terms, he updated his beliefs, or something.)
People are showing their appreciation for the fact that he listened. Doing so is a great positive reinforcement of community norms, and makes users happy to follow the norms as they get rewarded for doing so, as opposed to the opposing strategy of downvoting deviations from the norm, which might result in resentment, as they would experience only punishment.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should be posted in Discussion, and not Main.
4. Open Threads should start on Monday, and end on Sunday.