There was a major reasons why The United States wanted to have European influence out of Cuba. One of the reasons was that actually Americans were firmly opposed to colonialism and the Spanish occupation of Cuba was a daily reminder that one of the last remains of the European colonialism. They wanted it removed.
It was not a surprise that when Cuba's independence movements began, Americans enthusiastically support the Cubans. In a nutshell, American antagonism to European colonialism was one of the strongest reasons to support Cuban independence.