I've long ago come to realize that there isn't much at all that makes sense to you, but you might want to brush up on your history...
Spain was neutral during World War I and unlike its European neighbors, it didn’t impose wartime censorship on its press. In France, England and the United States, newspapers weren’t allowed to report on anything that could harm the war effort, including news that a crippling virus was sweeping through troops. Since Spanish journalists were some of the only ones reporting on a widespread flu outbreak in the spring of 1918, the pandemic became known as the “Spanish flu.”
-- SOURCE ARTICLE