The May Treaty, article I, states
"I. That the government of Cuba shall never enter into any treaty or other compact with any foreign power or powers which will impair or tend to impair the independence of Cuba nor in any manner authorize or permit any foreign power or powers to obtain by colonization or for military or naval purposes or otherwise, lodgement in or control over any portion of said island."
The US correctly realized that foreign entanglements are often problematic, especially for a young nation necessarily weak, and that allowing a foreign power to establish a military base on its soil could easily jeopardize the freedom of the people of Cuba.
Nonetheles, a few months later, the US did exactly that.