Because if he continued reading he would find valid points to refute his argument.
jla loves the Village Voice, which has regularly denounced Ronald Reagan as a greedy racist idiot - but jla thinks it's OK to quote people who slander Reagan, as long as they also slander Giuliani.
jla knows that he cannot argue that Reagan was an ambitious man - as all great Americans are. jla also knows that he cannot argue that Reagan didn't enjoy being President - because Reagan obviously enjoyed being President and that joy was evident in his face when he addressed the nation.