The US is easily the biggest target. I would think Wiki's justification is that the US has far more culpability in world affairs than most other countries. The

The US is easily the biggest target. I would think Wiki's justification is that the US has far more culpability in world affairs than most other countries. They get involved in disputes that most other countries can't touch. In terms of risk, the US has a massive intelligence and political footprint that simply leaks more. The opportunity and impetus to leak are simply greater in all regards. In comparison, China and Russia run much more despotic regimes. They have fewer qualms routing out political opposition, and simply have less open and democratic societies. There is a vastly smaller opportunity due to size as well.