How is he correct

The individual is correct in stating that there is no legal loophole that would allow New York State to force Trump to serve his prison sentence for the entire 4 years of his presidency, nor can Trump be pardoned from a state case once he is sworn into office. Here's why:

1. State and Federal Jurisdiction: The case in question is a state criminal case, and once Trump takes office, the federal government will have a different set of legal authorities and jurisdictions that supersede state laws. The federal government has the power to grant pardons and reprieves for federal crimes, but this does not extend to state-level offenses.
2. Immutability of Presidential Oaths: After taking the oath of office, Trump's powers and legal status are fundamentally different from those of a private citizen. He is protected by the privileges and immunities afforded to the office, which include resistance to certain legal actions, such as a state's attempt to prosecute him for a state crime.
3. Supreme Court Rulings: The Supreme Court's decision on presidential immunity applies to certain aspects of a president's actions during their term, but it does not alter the fact that once a president leaves office, they are subject to state and federal laws again. This means that any legal proceedings against Trump for state crimes would need to be handled with great care to avoid conflicts with his post-presidential legal status.
4. Political and Practical Considerations: The scenario described—Trump declaring New York in insurrection and arresting the judge—while dramatic, is not a realistic or legal course of action. Such actions would be politically explosive and could lead to immediate and severe consequences, including impeachment and removal from office, as well as legal repercussions under both state and federal laws.

In summary, the individual's response is correct because it accurately reflects the legal and political realities of the situation, emphasizing the limitations on state authority over a former president and the unique protections afforded to the office of the presidency.