You wouldn't be wrong to assume that when a country celebrates it independence day, they're celebrating the moment they won sovereignty, their freedom from a different country. For most Latin American countries, these observed days mark their declaration of independence from Spain (though it's key to realize that this liberations didn't apply to all: many enslaved people wouldn't be liberated until much later). But the Dominican Republic's independence day, celebrated on February 27, has nothing to do with Spanish colonizers, but rather the country's autonomy from Haiti in 1844, a fact that's set the groundwork for centuries of anti-Black animus.
The island of Hispaniola is home to two countries, with Haiti on the west and the Dominican Republic on the east. After 1844, the Dominican Republic was re-colonized by Spain between 1861 to 1865, and its freedom from the European colonizer arrived in 1865 when Black Dominican rebels, with the help of Haiti who feared that Spain would reestablish slavery, fought to overthrow Spanish rule in the Dominican Restoration War.
Despite, anti-Haitian sentiments are ingrained in Dominican culture. It led to the genocide of thousands of Haitians and Dominicans of Haitian descent living on the island, organized by Dominican dictator Rafael Trujillo in what's known as the Parsley Massacre of 1937. In order to move away from anti-Haitianism, digital awareness movements (like the use of the hashtag #1865) allow Dominicans to critically think about why we celebrate on February 27, and not on July 15, when the country gained its freedom from Spain.