I guess that U.S. Nuclear Regulatory Commission is required to report any unusual events in the plants in the US, which would be reasonable. A worker falling into a nuclear reactor pool is unusual. The report itself doesn't seem like it's anti-nuclear in any way, and it clearly states "no impact on the health and safety of the public or plant personnel".

If you're asking why it's interesting for HN, I think it's actually because people are fascinated with nuclear, in a positive way.