When Sam took over YC, it was already well established. He's done little to improve that reputation. As head of YC he secured personal deal flow, made connections, and ended up at OpenAI through those opportunities. What were his qualifications for taking over YC? PG liked him. Why did PG like him so much? Who knows. It wasn't Sam's accomplishments or experience, that's for sure.
Apparently this fondness for Sam was established "3 minutes" after meeting him. When I'm doing interviews and hiring, and the same feeling happens to me? I step back to examine by own bias. For PG? It was just that instant pattern recognition baby. Why question it.