Why was selecting George Washington to head the army the most important action taken by the Second Continental Congress?

Answer 1

This is a distinction made after the fact, meaning: the 2nd Cont. Congress did not meet and say, "This is the most important actio we can take - make Washington General." They met and made him General, and after the war everyone thought, "Hmm, look how we beat the British, making Washington a General was the most important action we could have taken back then". So looking at it from that perspective, some actually did not want Washington to be General of the Army when the 2CC met, it wasn't until he was routing the British did his natural ability to lead kick in and convince the country he was the right pick.