Sigh. Let me try one more time.
Why weren't they advised to avoid him to begin with? Wasn't the wholesale slaughter of an entire generation of infants worth avoiding?
Being able to see into the future - slaughter of infants - was not part of their skill set, so to speak, and is not related to intelligence. Hindsight can be 20/20, but most people don't have 20/20 foresight. You are looking at the situation with hindsight.
God works in mysterious ways. Why did He choose Peter who denied Him three times to be his first Pope or Judas who would betray Him? It is all part of God's plan, but that does not mean that we can fully comprehend His plan.