Nehemiah delivers a harsh rebuke regarding the public violation of the Sabbath, directing his anger specifically at the nobles and leaders of the people [ביאור שטיינזלץ, מצודת ציון]. He targets the leadership rather than the general public because the leaders failed to protest or stop the people from sinning. As a result of their silence, the full responsibility for these actions falls squarely on their shoulders [מלבי״ם].
The core of the accusation is that the Sabbath is being desecrated through the purchase of goods from Tyrian merchants on the day of rest [מצודת דוד]. This desecration actually involves three distinct violations [רלב״ג]. First, the very act of buying and selling on the Sabbath breaks a rabbinic decree. Beyond this, two direct violations of Torah law are taking place: the people are performing full labor, such as treading grapes in the winepresses, and they are denying rest to their animals by forcing them to work.