Romero Britto is a Brazilian pop artist famous for bright, colourful, commercial artwork, and babaca is Brazilian Portuguese slang for an idiot or jerk. Paired together, the phrase works as a blunt piece of internet slang rather than a formal criticism, which is why it travels well in short videos and soundboard clips even for people who do not follow art. It is mainly used online as a quick, funny insult for anything loud, commercial or pretentious, and its short length makes it easy to drop into memes, edits and reaction content.