Why did the members of the Philadelphia Convention reject Hamilton's Plan?

Answer: Because they feared the construction of a strong federalist government that would tyrannize them.

Explanation:

On September 17, 1787, after 16 weeks of deliberation, the Constitution in its final wording was signed by 39 of the 42 delegates present. The Convention had decided that the Constitution would come into force when ratified by the conventions of nine of the thirteen states. In June of 1788, the nine states required to ratification had already given its approval but the major states of Virginia and New York still had not. Differences of opinion on these issues led to the creation of two parties, the Federalists, in favor of a strong central government, and the Anti-federalists, that preferred a more liberated association of separated states.

In New York, Alexander Hamilton, John Jay and James Madison defended the ratification of the Constitution in a series of essays known as The Federalist Papers. These essays, published in the New York newspapers, featured the classic defense argument today of a central federal government with the executive, legislative and judiciary kept separate and that controlled each other.

Madison in particular wanted to push the Constitution back in the direction of his Virginia plan ... Its members, such as Madison, were delegates who had shown a greater desire for compromise and were chosen for this reason as most in the Convention wanted to finish their work and go home.