Why did the Catholic Church respond negatively to Copernicus and Galileo's discoveries?

Because back then, the Catholic Church stated that the Earth had to be the center of the solar system because God is perfect, therefore made Earth perfect, causing it to be the center of everything. This was wrong. Galileo and Copernicus had shared that the Sun was actually the center, not the Earth. This contradicted with what the church said, therefore what "God" said. The church called them out for blasphemy and they had to deny their ideas.