Sounds like a fetish genre "preference" that you can exclude, nothing more. From a list of genre preferences, it allows you to unselect what you don't want to choose from.
From a broad perspective, it sounds weird to limit based on certain words, but from a "restrict" mode in what is effectively a censoring app, you do see specific words being "selected" to limit access. I don't understand the context in wanting to exclude "asian", but I would understand wanting to limit specific word searches. Examples might be: Hustler, certain sex act name "x", WAP. ;-) If your kid suddenly gets told by someone to search for a specific word or phrase, you might want to put that word into the "exclude" list.