Um... just because of that?! Does the name "Yasser Arafat" ring a bell? Not to mention Henry Kissinger -- and less-famous names like Cordell Hull (who, as US Secretary of State, had opposed giving asylum to Jewish refugees in WW2, but was a tireless promoter of the UN).
Ten Controversial Winners of the Nobel Peace Prize
The list makes interesting reading -- and the winners were controversial for very different reasons