The other point is there was an exisiting insurgency,
Cuba wasn't exactly irrelevant to American interests, though; there was 100 million dollars worth of trade between the US and Cuba before the revolt started, and this plummeted to less than a fifth by 1898. From what I've read, the business community tended to blame the Spanish for this, and wanted them gone. I don't see an analogous situation cropping up over Aruba.
The other point is there was an exisiting insurgency, which meant the US had allies on the ground - same thing (potentially, at least) in the PI.
Beyond the economic ties between the US and Cuba, the underlying geopolitical realities were that in the Caribbean, Spanish (mis) rule over Cuba opened the door for adventurism by one or more of the European powers (cough -
the kaiser - cough) ... which was not something the elites in the US wanted to open the door to, certainly not in the Americas.
There's a reason the US opposed the French and Spanish adventures in the 1860s, bought the Danish West Indies in 1917, and generally respected the British, French, and Dutch colonies in the Western Hemisphere during this era ... it was the prospect of instability in the remaining Spanish colonies in the Caribbean that provided, however slender, a strategic interest in solving Spain's problems for them, no matter the cost to the Cubans and Puerto Ricans.
Best,