What happened to make the British victory at Camden, South Carolina, in 1780 the most devastating American defeat of the entire Revolutionary War?

During most of the American Revolutionary War the Battle of Camden in South Carolina was indeed an imbalanced win for British.

Notwithstanding the outbreak of diarrhea amongst the soldiers, on the morning of 16 August 1780, Continental General Horatio Gates decided to engage the army of British General Charles Cornwallis.

Many American soldiers retreated on the first notice of British reinforcements arriving.