GENEVA (AP) — Dozens of Western diplomats walked out of a U.N. conference and a pair of rainbow-wigged protesters threw clown noses at Iran’s president Monday when the hard-line leader called Israel the “most cruel and repressive racist regime.” The United States decried the remarks by Mahmoud Ahmadinejad as hateful — reinjecting tension into a relationship that had been warming after President Obama sought to engage Iran in talks on its nuclear program and other issues.