The three dots between thumb and index finger can mean almost anything. “Mi Vida Loca” is common, but so is “faith, hope, love”. In Europe I have heard it referred to as “the hobo tattoo” - signifying that the person has lived as a hobo for some time. I have heard older sailors here in Denmark call it “the sailer tattoo” as well. I have never heard about any references to white supremacy stuff, though.