Maybe I would have appreciated the article better if the title hadn't said "CSS optimization". That made me expect to find some secret to help me make CSS load or render faster. He really fixed a bug in the use of a CSS sprite file.
More interesting: someone finds a way to find other instances of sprite files being used incorrectly on a given domain. But I think Google PageSpeed would identify this for accessing a static file with query string.
However a notable developer hit a problem on a well-known site, diagnosed, proposed and explained a solution, and did it in a friendly, humorous way.
So there are a few lessons there on how hackers can conduct themselves in a positive manner in online communities.