I would trust the Source 1 i.e., the “Sworn testimony by American Sergeant in Congressional hearings in 1969” more because a sworn testimony is a gold evidence for the Congressional hearings. It won’t affect a person i.e., the Sergeant in any way. Maybe the testimony can get corrupted by lying, forcing and constraining, and the shaking the human memory. But in a speech by the General can affect his reputation as he can hid the truth and lie in his speech. So, the sworn testimony is more reliable than the speech.
The anti-federalists believed that the Constitution would take away critical powers from the states, and warned that without a Bill of Rights the government might also take away the rights of the people that were just won in the Revolution.