2) If Chait voted for Barack Obama who was attending Marxist conferences about the time Rand Paul was reading Ayn Rand, he's already demonstrated that this stuff isn't that important to him. Politicians evolve. Ask the same questions about those you vote for as those you vote against. If Chait was willing to take a chance on Obama in spite of Frank Marshall Davis and all the rest, isn't he being hypocritical not to give Paul the same benefit of the doubt?
3) People take from Rand what they want or need. Even Ronald Reagan called himself an "admirer" of Rand. I don't think he went whole-hog or that Rand Paul does either. She had an admirable side. Not everything she said was horrible or monstrous. Some of it was just good sense. She opposed some things that were worth opposing when not everybody did. Finding somebody who later became a politician quoting Rand saying basically what the Founders or George Orwell would have said isn't very damning.
I think what impresses new readers of Rand is the shock of recognition they get from her antagonists. Each of her bad guys has a counterpart in people running the country today. She understands statists perfectly and she understands where statism leads.
When you read about the car trip to the ruined Wisconsin city that was home to the defunct car plant, my god, she is describing Detroit 50 years in the future.