@austinmshauri When I had hispanic friends applying they mentioned that many of the Ivys used that definition and some were directly advised by adcoms to only put hispanic if they were at least a quarter. For hispanics that’s probably the most common “cutoff” point although it’s on your honor. I’m not sure if it’s officially stated anywhere or if it’s more of a widely accepted percentage to consider yourself a certain race. Native Americans sometimes need to have tribal affiliation in addition to a certain percentage (although I’ve heard their percentage can be lower than 1/4 as long as they have the affiliation).
But really, OP, what anyone else does isn’t your concern. They’re the ones that will have to live with their decisions.