Short question clips like this spread on soundboards and social apps because they work as a complete reaction in just a few seconds. The phrase are you five is a common teasing put-down in everyday speech, used to suggest someone is acting immature without starting a serious argument. Online, creators reuse the audio over gaming clips, chat screenshots and everyday fails, letting the line do the judging for them. Its popularity comes from that flexibility, since it fits friendly ribbing between friends as easily as public callouts in memes.