Final answer:
Americans supported the Cubans in their rebellion due to the similarities with America's struggle for independence, potential business opportunities, alignment with the Monroe Doctrine, and the brutality of the Spanish. Some shippers and businessmen supported the Spanish to protect their interests, and the Spanish monarchy feared the consequences of Cuban independence.
Step-by-step explanation:
The American support for the Cubans in their rebellion can be attributed to several factors. Firstly, the rallying cry of "Cuba Libre" reminded Americans of their own struggle for independence, creating a sense of solidarity. US businesses also saw the potential for investment in Cuban agriculture. In addition, Spain's exit from the Caribbean would align with the Monroe Doctrine, which declared American authority in the Western Hemisphere. Lastly, the brutal tactics employed by Spanish commanders, including torture and relocation of suspected rebels and their villages, evoked a humanitarian response from Americans.
In contrast, the Spanish received support from various quarters. Shippers and businessmen, particularly those in the sugar industry, supported the Spanish to protect their own interests in the region. Additionally, the Spanish monarchy feared that Cuban independence could spark other uprisings, leading to opposition to the rebellion.