Spanish assigns gender to most nouns, and the masculine form traditionally covers mixed groups. Latine replaces the gendered o or a with an e, a letter already used in gender-neutral Spanish words. It grew out of gender-inclusive language movements in Spanish-speaking countries, where the e ending is also used in words like elle, a nonbinary pronoun.
Because it can be said aloud easily in Spanish, supporters see Latine as more natural than Latinx, which many Spanish speakers find awkward. Some US organizations and universities have switched from Latinx to Latine for that reason. Use remains limited, and Spain's Royal Spanish Academy has not accepted gender-neutral e endings.
The broader point is that no single label fits a population of more than 60 million people in the US with roots in many countries and races. Many people identify first by national origin. ARD uses the terms communities use for themselves and names specific groups when the facts apply to them.