Why wouldn't they. Everything we're proud of as Americans goes directly against conservative principles. Separation of church and state, allowing people to live their own lives and make their own decisions free from state interference, giving people a say in their own governance, caring for one another, ensuring as best we can that everyone has a bed and no one goes to that bed hungry, giving people who've made mistakes a way in from the cold in order to fully participate in society, all of it is fundamentally counter to what conservatives want, and they're simply wrong.