Sinakhone Keodara reached his breaking point last July. Loading up Grindr, the gay dating app that presents users with potential mates in close geographical proximity to them, the founder of a Los Angeles-based Asian television streaming service came across the profile of an elderly white man. He struck up a conversation, and received a three-word response: “Asian, ew gross.” He is now considering suing Grindr for racial discrimination. For black and ethnic minority singletons, dipping a toe into the water of dating apps can involve subjecting yourself to racist abuse and crass intolerance. “Over the years I’ve had some pretty...