Because those that knew the trade and worked hard for the job often did not get the job unless they knew someone. And sometimes people in the spoil system did not know how do their job. It wasn't merit based. Like is someone worked their whole life to be a doctor and a high school graduate becomes a doctor because they knew a friend who could hire them.
Federalists: Believed in Federal power, representative government, supported Great Britain in the 1890s, favored a strong Central government.
Anti-Federalists (Democratic Republicans): State power, Self-Government, France, State power.